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K2 Manual

1. 1 dq LL 3 7d x Jd 5 L qp p oo j j Jj J _ L Ra jas d 5 10 foo j j j j 2 135 16 50 o j j jy L jd we cp pm 4141 pf 24 135 1104 j j jJ L 135 135 1510 1 l 16 RF BOARD Shaded areas indicate transmit mode voltage measurements Ref Pin VDC Ref Pin VDC Ref Pin VDC Ref Pin VDC Ref Pin VDC Ref Pin VDC DI A 00 1012 s 00 ui t 60 E mr Lu m C 175 60 2 so Lx as Tp o 3 19 1l 75 4 00 1 21 D3 50 2 00 s c 6 foo D4 A 80 Qi 00 7 joo 23 00 p ea E Oa 8 00 5 50 A o jo bees 1 C 180 7 s 00 10 ois P 7 0 138 12 pe A 80 G 22 u oo a ou NL ED 2031 2 o0 9 joo 90 1 i4 m A o c ao n foo oo 12 fia 1 T C 175 S i2e3 14 oo 11500 3 j oc 11 D 63 15 oo 12 oo 4 50 j G 180 joo 16 oo 13 40 Ss D ioo S os m7 oo 14 50 F oe D 80 1
2. 60 1 gt 9 CQ o lt gt 620 820 24728104 OLH 6H ZH ides 9 8 lt gt 0 9 a 144005 TIVLSNI LLO me m zaraa H3INnOO 099901 L T 0n lt 292 2622 D Ds BT ogg C D o 222 9 We N 0 15 H O Sd orp c gt EEEE EO O 299 do C3 00 3 60 SI T F QuvOa TANVd LNOH4 quvog seu T ais JOHINOO 94 T a 0 5010 9010 8r T 2 RN ER x _ es S im 2 SLS dS JEN o BE A MO dd S ER E Treas 919484 eee Wap C Js 991 207 poor R0 OE lt gt A lt gt ZL gt lt gt edd 0040 1019 9001 999 866 260 yen LL i 0 1 089 _ 229 ScO OLX g c i 8919 2 o 8 I po T 8 969 OO o 6 Lud gt 149 C Y Lea lt D Ty ley C o 0 lt gt 2 Joso pM 90 7001 26210 061 Jozo __ 90 oq 3 284 er 23 ou r C C gt L aa 91 119 1 zs5 LIH
3. R11 LMC660 2 33K 47K C24 VPWR D3 on PCB AUXBUS PN2222A 40 TXD PA AUXBUS Raar BA D 15 ae C12 ICLK C45 5027 247000 C43 8T Sep V SMTR IDAT dp V pe a ALC SENSE SR RD Quad 8 bit DAC C34 001 V ALC 12V V SENSE lt SR DOUT 1 2 1 35 V PWR SLOW AGC srok of CW key shaping XZ 82K RP3 47K V POTS SR WRT 12 mod solder on back see text 13 R12 820 ENCA AGC OFF U10D V RP2 P ET 5V FCTR ei 30 IDOT PTT z 5 7 V RFDET RB 01 7 82K RP3 47K 475 DASH RP4 RPA RX 10 V BIAS XFIL 3 U8 ei een Bo MAX534 2 8 U10C a C38 ENC B Freq Ctr 999 24 MUTE SZ 82K RP3 47K Input SCK ti 100kHz 40MHz Q9 L DAC2CS B P6 MPS5179 Y MPS5179 PLLCS 1 DAC1CS U6 RP7 4 Voltmeter Source 18C452 33K v Vol EXT INT 2 oltmeter Input E rh Current Sense MCU OS EY Note Current sense resistor 55 18 P5 mm P7 is R115 onthe RF boarda 12 8V Low Dropout Reg 02 SIE 51 LM2930T 8 8V Switching 42 8A U4 NOTE 1 0 1 R8 IN OUT lt 8T Voltage Sense 100 aa ES C16 2 R9 1 1 15 Es 2N3906 806K 1 En ep i USA NB 100uF L JL Mute 5 4550 lt LMC6482AIN RP1 6 122 7 V SENSE 3 9K S i ds wo pe v 5V Reg 196K 1 USB 0 00 5 10A PN2222A 78 05 GF 9 RP1 02 A resolution R7 1 78k 1 U5 3 9K 4 IN OUT 5A 8R 10 a
4. NIGHT 23 SO through S23 connected to DS1 only SO and S23 shown 1 ae 40 35 30 25 K 6 55 2 56 bi S7 jas 14 S15 16 REC PF1 PF2 EDIT Q1 LEVEL 0 AT d 9 PN2222A a 4 0V DAY 18mA LED D7 DO D3 D1 D7 DO 2 7V NIGHT 6mA LED RP2 120 based on LED Vf 1 9V DO D1 D2 D3 D4 DS D6 D7 RFI Pushbutton Switches First switch label corresponds to switch TAP Second label corresponds to switch HOLD S7 S16 can also be used as a numeric keypad 2 3 4 5 7 8 9 10 10 9 8 7 5 4 3 2 LED Array 5 2 C9 R16 R15 01 15K 10K 5A BANK1 SPD RD MIC RD ENC RD E 5 Shaft Encoder R1 5K c Keyer Speed Qo 6 SPD RD ccw A cw ppm _ 047 D4 SRRD SRCK SRDIN 5A R2 5K C2 U3 Power Out An 01 6B595 BANK1 cow 4 E 5 To RF Board P1 a 2 sa Oe SS E RA R5 5K 12 13 14 15 16 17 18 19 20 RIT XIT Offset V7 MIC 2 S CCW enm a lt 67 5 cw DOT PTT o m D6 x 1N5817 V POTS lt V POTS R7 4 7K R3 R6 4 7K 2N3906 R13 68 1K 1 C4 C5 C6 C7 01 01 01 01 AF Gain Mic Config ICLK IDAT MIC RD 5K audio taper Elecraft K2 Front Panel Board These components are supplied with SSB adapter Rew Daie Shi E Swartz C 10 6 02 1 of 1 Appendix B
5. C163 01 103 CI62 047 473 164 01 103 7 C170 047 473 7 C166 047 473 7 C179 100 101 C182 180 181 7 185 0 1 104 C184 01 103 CI81 01 103 51 Install the following ICs aligning the notched end of each IC with the notch on its component outline U6 1 at the front left U6 LMC662 gt US LTCI45 104 145170 U3 11252 010 NE602 7 U9 11252 011 8602 012 MC1350 Install U8 78L05 which has a plastic TO 92 package like a transistor US 1s located near the front left corner of the board Option bypass jumpers W5 W2 and W3 are located on the right side of the board near the crystal filter Use component leads to make these jumpers or remove the insulation from appropriate lengths of green hookup wire These jumpers should be formed so that they lie flat on the board and should not touch any adjacent components Test points TP1 TP2 and are round yellow single pin female connectors TP1 and TP3 can be found in the synthesizer area of the board TP2 is near the SSB option connector J11 Install and solder all three test points LJ install RF choke RFC13 100 uH BRN BLK BRN near the middle of the board Orient the first color band to the left Install the receive mixer Z6 TUF 1 or TOP 1 below the ELECRAFT label at the middle of the board Make sure that Z6 is lined up with its component outli
6. 850 gt Ack XNV 22 veu T C gt N gt JS 8H cody 199 j ed 9giu 1 F cD Bro P T F 2 2919 C gt 00 589 T gt 8 g AD LAM C wt 02 2 s94 D fh pak 910 IO 14vuoaTa 20020 ge 211 D A T dH 2M o Gel zn 8 mi 9220 9 ceu T ELD 6220 C gt EES 9210 09H Zy 23 2229 21 C L O 0 260 LED ma 0220 N 6 3 Sr soc py 089 CD 9619 1 22 Aa ATT TA lt gt 49 2 gt Z1 6125 QO NN zizo C 015 ER 8 4 n I os a 2 ge S 8 xnv i Q 51 b i GLO 91 aa l d e hole a ul en aD lt gt 611 o 021 3 59 Of o Z o o zozo C gt A 025 ceo do mMm jo d ee xU I Hiru o er 1020 o ZSH r o M vo 0 211 280 C D 11 Ir 0610 AzS 5 T E MDa Jan 2612 lt gt gt c 2d Parts Placement Drawing Bottom Appendix F SQV31 AV 154 N38 LON OG l F R110 R100 20 PUSHBUTTON SWITCH SPACING TOOL INSTALL SOCKET FIRST PCF8566 AF PT DN MIC CONF
7. clin d onm AQ S hodic ee b p Q ELECRAFT K2 TRANSCEIVER BAND DISPLAY 2 2 TRANSCEIVER 7 MODE AB A B E 5 9 20 40 INE in J vox omm sein BAND ANT 1 2 5 7 PRE ATT AGC XFIL pi NB ANT2 PRE ATT A B XIT E E Je STORE TUNE KEYER POWER SPOT CW RV AFIL MENU NB e lt MSG 4 LEVEL REC qp Miti 3 E OWNERS MANUAL ELECRAFT K 2 160 10 Meter S S B CW Transceiver Owner s Manual Revision F January 29 2004 Copyright 2004 Elecraft LLC All Rights Reserved Elecraft www elecraft com Box 69 Aptos CA 95001 0069 831 662 8345 Fax 831 662 0830 2 ELECRAFT Table of Contents 1 eee 3 2 SPECIFICATIONS u uu ll ein tec 5 3 PREPARATION FOR ASSEMBLY eU ERIPUIT E ee masa tua e asi 7 4 CONTROL BOARD pu LULA 13 5 FRONT PANEL BOARDS u uuu 22 IMP BOARD 33 7 PINALA SEND Vee 78 8 OPERATION 81 9 uuu uuu IUE MILD 106 10 SOP TONS 113 PARTS LIS u an S D Sun LLL APPENDIX SCHENMATIC u u EIL D u DII DLE APPENDIX B BLOCK DIAGRAM APPENDIX APPENDIX D TROUBLESHOOTING cere
8. 209 x Q18 eer 27K 181 C86 OSCOUT PHV V gt Buff 12uH NOTE 1 0 1 204 REFOUT PHR R24 R25 U6B R17 ee FIN PDOUT 100K DIS nel 2 7K 2 7K s 100K 500 L VSS i 1N4148 C64 LT1252 RP2 07 IPLLCS D LD C88 L 4 b em 10K 120 68 2 SCK x 92 2 P I RX VFO 1 2 4 3 RFC14 NOTE 3 i yh RP2 022 Bit is 017 18UH T 1 2uH 1N4148 R14 MV209 1SV149 5 108 v x TP1 R20 7 279 R11 C100 R19 R12 560 001 2 7K 560 lt C63 U5 8B 01 LTC1451 1 sck D 5B 7 020 21 D22 V 2Vpp 2 3 2N7000 spo gt 1 Mv209 1SV149 BO gt 8B 78105 5B me VFO ALC 4 4 aA 47uH C60 N 100uF 5 D11 R10 C58 12 Bit DAC U6A 1N4148 01 Vout 0 to 4 096V LMC662 nas 2 3 1 L VFO Range Selection Relays are shown in RESET 8B 2 C103 ae 8 position See relay table key C62 RB 12K RD 1 8K 2203 C73 ais 5 gt 47 C75 PN2222A Rt 10K RC C71 C72 470 R18 Thermistor 2 2K NOTE 2 82 270 TM 4V 4 5 Thermistor Board L replaces RP3 on PC board J3 12V DC V BIAS XFIL 2 J1 a Key Keyer Paddle 12V 5A 8A gt 2 5 9 010 R2 R1 2 4 8 10 12 14 16 18 20 22 24 26 28 32 34 36 4 10 12 14 16 18 20 Aux 12V 2 12 ve va 22 24 26 2 ERE oe d C1 zr 12 lt Q lt 12V 5 8 x voLi 9 Q u 3 SR DIN 0 05
9. Figure 6 29 69 Before installing T4 verify that the screws holding the 2 D fastener beneath it are tightened and that 4 internal tooth lock washers were used It is important that these screws not come loose sometime after T4 has been installed Install T4 to the right of T3 inserting leads for the 1 2 and 3 4 windings into their matching numbered holes T4 should rest directly on top of the screws that secure the 2 D fastener beneath it T4 should also be parallel to the board not tilted to one side Pull the leads taut on the bottom and bend them to hold the transformer in place Do not solder T4 yet Use two 2 5 cm lengths of bare hookup wire to form the 5 6 and 7 8 windings on T4 Figure 6 30 These are more accurately described as inks each being just a single turn Route the bare wires through the core first then bend them down and insert them into their numbered holes Do not solder yet Figure 6 30 Adjust all of the windings of T4 as needed so that transformer 15 positioned directly above its component outline Pull the leads tight on the bottom then solder Inspect all four transformers in the transmitter area closely on both top and bottom for shorts or cold solder joints 70 AN PA transistors Q7 and Q8 28C1969 must be installed on the bottom of the PC board with their metal tabs facing away from the board as explained in the following steps Locate the com
10. 4 when you hold and B AND together to initiate Direct Frequency Entry To get to 432 100 MHz you d then enter 32100 Controlling transverter relays The 8R HOLD feature can prevent excessive transverter relay switching in CW mode To change the 8R HOLD setting locate the menu entry primary menu edit the parameter and tap DISPLAY to select 8r hold This 1s the default setting and 1s recommended for use in all operating modes whether or not transverters are used Using the K60XV option with transverters In addition to 60 meter coverage the K60XV option provides a low level split RX TX path transverter interface This interface can be selected on a per transverter band basis by adjusting the OUT field for an output value in milliwatts L0 01 L 1 27 In mode power in mW is displayed plus LP for low power e g P1 00 LP The K60XV also provides a buffered relay keying output and logic outputs for transverter switching Additional control capabilities are available with the Elecraft KRC2 programmable band decoder Refer to the K60XV and KRC2 manuals ATU considerations Use caution when connecting both a transverter and an HF antenna to the KAT2 you could accidentally transmit at high power into the transverter For example suppose that you have T RN1 set up for an I F of 14 MHz and a 1 0 watt power limit If you switch the K2 to 14 MHz where there is no power limit you mu
11. 6 Key the transmitter using the hand key does not activate the sidetone Measure the AC voltage on pin 25 of U6 Expected 2 5 Vrms Actual Un key the transmitter 7 Move the DMM probe to the drain of Q5 control board 2N7000 Key the transmitter and measure the AC drain voltage Expected 2 4 Vrms Actual If this 1s zero either Q5 1s defective or there 1s no drain voltage supply from pin 1 of U8 MAX534 D to A converter 8 Measure the AC voltage on pin 7 of U10 LMC660 Expected 0 5 Vrms Actual 9 Measure the AC voltage on pin 8 of U9 LM380 Expected 0 5 Vrms Actual 10 Measure the AC voltage on pin 6 of U9 Expected 0 5 Vrms Actual This signal should also be present on the speaker jack P5 pin 1 RF board 11 Return the ST L setting to 030 12 Use the button to put the transmitter back into mode U ALC control board 1 Make sure the POWER control is set for 5 watts and that you re in CW Operate mode 2 Set up the DMM for DC volts 20 or 30 V range 3 Power Control Test VPWR line The VPWR line pin 2 of U8 MAX534 is where transmit power control begins On key down the microprocessor U6 starts increasing the voltage on VPWR until it sees the desired power indication from the RF output detector RF board sheet 3 lower right hand corner To test VPWR set the DMM for DC volts then measure the DC voltage on pin 2 of U8 when Ila is pressed Expected
12. GND Q2 2 7 44 C14 C19 2N3906 2N7000 VOL2 zr Not Used 047 ae 047 5 6 7 8 Q4 C4 RP1 AGC OFF RP6 2 21 54K 0 47uF 3 9K ah RX 22 C6 isLow acc DH 2 1 AF Am 1N4148 047 Si V RFDET a p en R5 33K 912 10 dE 8 b C9 8A RP6 001 PES NE602 R3 Di 5 1K z 9 0 5 on 1 10K 1N4148 9 o lt lt a DE lt LM380N 8 9 2 jma LL lt 065 O 4 12V 5A 8A gt lt gt gt a 012 lt G QOO ppg Od 82K 10 2 5 s E 3 m 047 C29 10 lt 2 7 C8 77 7777151 220uF 01 6 5 1 OUT 220uF cw 50K C3 AGC THR 01 R F GAIN xt 8R T vou 95 n 12V 5A 8A Q 56 rx 8 re a dg 01 C7 S x mcm 5 Sa a O q 2 x1 330 RP6 t m gt lt z 5 068MHz 5 1K eae BR XL mS P2 Board J7 Board J8 I F OUT Elecraft K2 Control Board To RF Board J6 By W Burdick Rev Date Sht E Swartz F 1 27 04 1 of 1 NOTE 1 Jumpers are used at R18 and R19 They must be removed if the Audio Filter option is installed Ey bottom of PC board Appendix B PLL Reference PLL Synthesizer Oscillator Ags 12 090 12 100 MHz 15 NOTE 3 C95 01 i VFO 21 is C65 12 096MHz X1 5B A a6 019 D 100uH C94 D13 RFC10 10pF D 144148 OSCIN VDD H 023
13. Ref Description Qty RA 33K 1 4W Resistor org org org RB 12K 1 8W Resistor brn red org 1 2 2K 1 8W Resistor red red red pu 1 8K 1 8W Resistor brn gray red Thermistor 10K 3 TETTE orange body with black and brown stripes near leads MISC 24 Green Wire Insulated solid wal cal 30 cm n Locate the thermistor printed circuit board One side will be labeled with THM and the letters A through F All components will be installed on the labeled side and soldered on the other side Install 1 8th watt resistors RB RC RD RE and RF in their respective positions as shown on the board Color codes are listed above be sure to check them carefully Do not pull on the resistor leads as they may be fragile Bend the leads outward Solder all of leads Trim off excess lead length Install resistor 33 1 4 watt Solder and trim its leads Locate thermistor which has an orange body with black and brown stripes The thermistor is fragile so avoid bending its leads any more than necessary Insert the thermistor at THM The part is symmetrical and can be installed in either orientation Po sition the thermistor body so that it is just touching the circuit board Solder and trim its leads Remove insulation from 6 15 cm length of green hookup wire Cut the bare wire into 8 pieces of about 0 75 2 cm in length 49 LJ The remaining 8
14. All resistor and RF choke color bands are provided in the text along with their values However it is helpful to familiarize yourself with the color code to allow you to identify these components without having to refer to the text or parts list each time The color code chart Figure 3 4 shows how to read the four color bands on 5 resistors 1 resistors are similar except that they use five bands three significant digits multiplier and tolerance For example a 1 500 ohm 1 5 k 5 resistor has color bands BROWN GREEN and RED A 1 5 k 1 resistor has color bands BROWN GREEN BLACK BROWN The multiplier value is 1 rather than 2 the 1 case because of the third significant digit Because 1 resistors have color bands that are sometimes hard to distinguish clearly you should always check their resistance using an ohmmeter The markings on RF chokes reflect their value microhenries Like 5 resistors chokes use two significant digits and a multiplier Example an RF choke with color bands RED VIOLET BLACK would have a value of 27 uH Tools The following specialized tools are supplied with the K2 050 1 3 mm Allen Wrench short handle 5 64 2mm Allen Wrench long handle Double ended plastic inductor alignment tool ELECRAFT Color Code Tolerance gold 5 silver 10 Multiplier second Digit First Digit Color Brown Red Orange Yellow Green Blue Vio
15. Auto Repeat Any message memory can be auto repeated when played To auto repeat tap MSG as usual then hold the desired numbered switch 8 The message will then play back continuously until you tap MSG again or hit your key or paddle The buffer will flash at the end of each transmission e g B6 Note You cannot change the frequency with the VFO knob during a repeating message but you can use RIT if enabled to listen above and below your receive frequency between calls Setting the Auto Repeat Interval The length of the pause between messages during auto repeat can be programmed using the RPT menu entry 0 255 sec Long delays are useful for beacons 97 Message Chaining and chain repeat While a message is playing you can tap 0 48 to chain a message onto the end of the current one The buffer number will be displayed twice once when you hit the numbered switch and again when the chained message starts To chain a repeating message onto the current message HOLD rather than TAP the numbered switch i e use 4 3 Chaining 1 useful during contests For example you might set up message 5 as OSL 73 and message 6 as CQ TEST DE N6KR You could then hit MSGJ at the end of a QSO to sign with the previous contact then begin a repeating CQ CW Reverse CW Reverse allows you to listen to CW using the opposite sideband Sometimes this can eliminate or reduce interference from a strong
16. See Circuit Details 88 Filter Settings CAL FIL This section explains how to use CAL FIL to select the bandwidth and BFO settings An example appears on the next page The Elecraft web site provides information on other filter setup methods including a method that uses a personal computer sound card For a discussion of how the crystal filter and BFO settings are related see page 107 Basic CAL FIL Setup 1 Connect the frequency counter test cable to TP2 BFO 2 Set AF GAIN high enough to hear some background noise 3 Switch to a band between 160 m and 17 m The sideband 15 inverted on 15 m and above which may be confusing during filter setup 4 Select CW mode using If a bar appears above the K2 1s in CW Reverse mode hold to select CW Normal mode 5 Tap X FIL until FL 1 is selected Tap MENU and scroll to CAL Hold to move the underline to OFF then scroll until you see CAL FIL Finally hold again to activate the filter display Filter Bandwidth Display The initial CAL FIL display shows the present filter bandwidth and the operating mode e g FL1 1 50c The number 1 50 indicates a bandwidth of roughly 1 50 kHz This parameter has a range of 0 00 2 49 Above 2 49 the parameter changes to OP1 OP5 which can be used to select optional filters For example the filter on the SSB adapter KSB2 is OP1 Note the present bandwidth setting then try using the VFO knob to change
17. This oscillator takes its output from the crystal itself resulting in fairly low harmonic content This results in very slight pulling of the oscillator frequency as you adjust the output level but this is of no concern for signal tracing The oscillator will run on voltages as low as 8 V but 12 V or more is recommended to guarantee enough output for all signal tracing steps The components are not critical and can vary 20 with little variation in performance Nearly any NPN RF transistor will work in the circuit O1uF 10 MHz see text 2N2222A OUTPUT 2N3904 etc Level 10K 50 or 1000 non inductive Figure 2 Any crystal frequency that falls in or near a ham band can be used but 10 MHz is recommended since our signal tracing measurements were done using this band If you have only completed the K2 up through part II of the RF board 40 m you ll have to use a crystal in the 6 8 to 7 5 MHz range You may wish to build the oscillator into an enclosure fitted with a BNC connector and level control Use short leads for all wiring Use very short leads 2 or coax to connect the signal generator to the K2 s antenna Jack Band Pass Low pass Filters Filters Synthesizer RCVR Figure 3 Receiver and Synthesizer In the following steps you ll use the RF probe and other techniques to find the stage where the received signal is getting attenuated Figure 3 shows the approximate locati
18. making sure all pins make good contact with the IC socket Check the 4 MHz oscillator 075 090 EEPROM test 1 Remove the bottom cover and verify that all failed pins of U1 s socket are soldered as well as those of the 6V regulator RF U2 and U1 s 091 EEPROM test 2 4 MHz oscillator RF Z5 failed With power ON check all voltages associated with U1 You should see 6V at pins 1 and 20 at all times even when the IOC is sleeping not being accessed by the 081 AuxBus problem Y ou may have an option board installed that is causing a problem with the AuxBus Try removing each option board and turning power off and back on Verify that R64 is installed RF board near UI Check the voltage at pin 1 of the IOC RF U1 If it isn t approximately 6V U2 may be bad 6V regulators Check the voltage at pin 28 of the IOC RF U1 It should be between 5 and 6V If it is zero volts you probably have a short somewhere on the AuxBus line Turn power OFF then measure pin 28 of U1 to ground If it is a short pull the control board out to see if the short is on that board If the voltage at pin 28 1s between 5V and 6V try pressing the BAND button a number of times while watching the voltage carefully use an oscilloscope if possible The voltage should drop below 5V briefly if the MCU CTRL U6 is sending a message to the IOC If the voltage does not change at all the MCU itself may not be sending AuxBus messag
19. 0 68 uH BLU GRY SILVER RFCS 10 uH BRN BLK BLK __ R50 1 5 ohms 1 2 watt BRN GRN GLD _ R48 120 BRN RED BRN R47 47 YEL VIO BLK R43 22 RED RED BLK __ R42 4 7 ohms YEL VIO GLD RA4 2 7 RED VIO RED Make sure you have separated remaining slug tuned shielded inductors into 1 uH and 4 7 uH types Install these inductors in the order indicated below on the top of the board These inductors are difficult to remove once soldered so double check the part numbers The 4 7 uH inductors are labeled T1005 and the uH inductors are labeled T1050 L3 4 7 uH T1005 __ 14 4 7 uH L8 4 7 uH L9 4 7 uH _ L10 1 uH T1050 L11 1 uH L12 1 uH L13 1 uH ELECRAFT AN TO 220 package transistors Q6 7 and 8 look identical but Q6 is different Locate the two 2SC1969 s labeled C1969 Q7 and Q8 and set them to one side The 2SC2166 transistor C2166 will be installed first Attach a self adhesive thermal pad to the PC board on top of the component outline for Q6 The hole in the thermal pad must be aligned precisely with Q6 s mounting hole on the board Prepare the leads of Q6 as you did with the voltage regulators on the Control board Figure 4 4 page 16 using gradual bends to avoid lead breakage Insert Q6 as shown by its component outline Secure to the board using a 4 40 x 3 8 9 5 mm screw 4 lock washer and 4 40 nut T
20. 100 temperature calibration S LO S HI S meter calibration FIL crystal filter configuration and PLL VFO calibration Once you select a CAL function holding again activates the function The selected CAL function remains active until you tap MENU again which returns you to the menu Another tap of MENU returns you to the normal K2 display In the following section you ll activate the CAL FCTR frequency counter function For now just tap MENU once twice to return to the normal display Frequency Counter Probe Assembly LJ In the bag labeled MISCELLANEOUS you ll find the components for the frequency counter probe Figure 6 14 These components include a 10 pF axial lead capacitor two crimp pins a 2 pin housing and a 1 male connector probe tip Cut a 7 18 cm length of RG 174 cable and carefully remove 1 2 13 mm of the coax jacket from each end Be careful not to nick the braid 45 Separate braid from center conductor at both ends Remove 1 4 6 mm of insulation from each center conductor At one end cut the braid off completely right at the coax jacket a ground connection will not be needed for frequency measurements The braid should be twisted into a fine bundle at the other end Solder crimp pins onto the center conductor and shield at the housing end of the cable Solder quickly so that the heat from soldering does not melt the center insulator of the
21. 14 00 j C 2 _ OUT 30 50 15 jose jJ j j Qu E 02 us IN 137 3 16 Mose KI EMEN mi UN L L gt 11 4 s 1 3 L 1 60 1139 J Oo joo p Cp 3 gd d d jd 7 15 FRONT PANEL BOARD approximate and or may fluctuate not accessible due to LCD Ref Pin VDC Ref Pin VDC Ref Pin VDC Ref Pin VDC Ref Pin VDC Ref Pin VDC 34 30 35 j 5 19 Joo C 150 135 6 406 20 joo j 32 135 7 2066 J 2 e 450 5 J j j j 1 1 1 4 7 pog 4055 1221 24 a a 35 35 lo foo j J p 1 11 1 1 qs ne 3p Jo de d 4 1 7 Lo 1 8 as j j j j 161 1 65 3558 j jy EE NEL MN po gs C Cj jg rw j P cp o qd o o b 191 j j 101 j 4 so j j jy 1 2111 Tq 3 4d 5 2 je de d 3 ud 7 j 7 5 12 50 j j 10 _ P Lo Lo 1 1 1 p qwe gp qo 215700 __ qp j d 4 cw ob o d 171 j H so 16 09 j j j j j 1 250 7 0 j L
22. A comprehensive mini manual is also available for the K2 see our web site for details Connections Power Supply You can power the basic K2 without the KPA100 amplifier from any 9 15 V DC power supply A mating connector for the DC input jack 1s provided with the kit Current drain 15 typically 1 5 2 A on transmit but can be over 3 A at the highest power settings or with high SWR See Current Limiting below Internal Battery An optional 12 V 2 9 Ah rechargeable battery can be installed inside the K2 model KBT2 A 14 0 V power supply can then be used to recharge the battery and power the transceiver If an external battery is connected the internal battery must be disabled using the INT BATTERY switch Low Battery Warning If the supply voltage drops below about 11 V you ll see a brief LO BATT message flashed on the LCD once every 8 minutes approx If this happens reduce power and recharge your battery For tips on battery operation see page 100 Self Resetting Fuse If the K2 s internal 12 V line is shorted to ground fuse F1 will temporarily open limiting current drain to about 100 mA The display will remain blank If this happens turn power off until the problem is located and corrected Current Limiting You can specify the maximum transmit current see CAL CUR page 87 You ll see HI CUR on the LCD if the programmed limit is reached 50 60 Hz Interference Do not place the K2 beside or on top of any equ
23. C195 C204 C207 C208 C216 C223 001 Monolithic Cap 102 C52 C53 C54 C55 C58 C61 C62 C63 C87 C95 C107 C108 C109 C110 C113 C114 C115 C118 C119 C120 C121 C129 C135 C141 C142 C143 C145 C146 C155 C158 C159 C160 C161 C163 C164 C165 C168 C172 C175 C181 C183 C184 C186 Monolithic Cap 103 C92 C177 022 Monolithic 223 E530056 C90 C94 C117 C138 C156 C157 C162 C166 C170 C196 C224 C59 C65 C67 C86 C124 C130 C131 C133 C139 C151 C176 wl Pol N al gt 515 TI 7 Monolithic 473 C178 C185 Monolithic 104 C45 NPO 1 black top E530068 C33 2 2 pf alt 2 pF NPO 2R2 or 2 E530047 C22 2 7 pf alt 3 or 3 3 pF NPO 2R7 3 3 3 or 3R3 C6 alternate 5 pF E530048 C68 C21 NPO 10 or 100 see page 9 E530006 C28 C29 C219 NPO 12 or 120 E530058 207 200 530059 C198 2r orar 2830060 C43 C47 C116 C213 NPO 33 or 330 E530064 TI TI TI TI TI NO O1 cO Page 1 28 43 11 13 GOO a a RF Appendix K2 RF Board Parts List p n E850001A and E850001B PICTURE Designators Value Description Part Number QTY C221 39 NPO 39 or 390 E530036 1 C20 C24 C73 C203 A 1 4 C31 C35 C122 C228 NPO 5
24. If the display shows 0 0 volts P7 may be in the probe position In time date DSP display mode the LCD will show either time e g 08 05 00 or date e g 11 28 02 or DSP settings You can toggle between time and date by holding and B AND together Refer to the KAF2 or KDSP2 manual for details on setting the time and date as well as other features 91 Frequency and Band Selection The basic K2 covers 80 10 meters and you can also tune well above and below the ham bands 160 meters can be added with the K160RX option and 60 meters with the K60XV 60 meter users will probably want to set up channel hopping see page 99 Transverter Bands The K2 provides up to six programmable transverter band displays for use with external transverters Refer to the TRNx menu entry page 105 Transmit Limits Some countries require transmit to be disabled outside of specified amateur bands If you key the transmitter with the VFO set outside fixed limits you ll see End on the LCD You can change bands in one of three ways tap or BAND hold memory recall see below use Direct Frequency Entry described later Whenever you change bands or recall a frequency memory a number of parameters are saved in nonvolatile memory EEPROM This update also occurs periodically if you ve moved the VFO see Backup Timer The parameters that are saved on a per band basis include A and B V
25. Limitation of incidental or consequential damages This warranty does not extend to non Elecraft equipment or components used in conjunction with our products Any such repair replacement is the responsibility of the customer Elecraft will not be liable for any special indirect incidental or consequential damages including but not limited to any loss of business or profits ELECRAFT 2 Specifications All measurements were made using a 14 0 V supply and 50 ohm load unless otherwise indicated Values are typical your results will be somewhat different Specifications are subject to change without notice See option manuals for additional specifications General Size Cabinet 3 0 H x 7 9 W x 8 3 D 7 5 x 20 x 21 cm Overall 3 4 H x 7 9 W x 9 9 D 8 5 x 20 x 25 cm Weight 3 3 Ibs 1 5 kg excluding options 9 to 15 VDC reverse polarity protection internal self resetting fuse Supply voltage Current drain Receive 120 150 mA in minimum current configuration 180 250 mA typical 2 0 A typical at 10 watts programmable current limiting Transmit PLL synthesizer w single VCO covering 6 7 24 MHz in 10 bands fine steps via DAC tuned reference Frequency control Current varies with band supply voltage configuration and load impedance We recommend a minimum 3 5 amp power supply Frequency ranges MHz Basic kit 3 5 4 0 7 0 7 3 10 0 10 2 14 0 14 5 18 0 18 2 21 0 21 6 24 8 25 0 28 0
26. Misc Grill Cloth Must be cut to speaker size see text E850089 3x3 Misc Heat Shrink 3 16 dia For counter probe E980028 4 Page 3 Misc Probe Wire Relay Table Diodes SET Relays MV209 1SV149 BPF LPF 1Nxxxx 160m K2 160m K1 H 80m K2 K3 K8 K13 IL 60m K1 60m K1 12 K13 K14 40m ALT K1 K12 K13 K14 40m K1 K12 K14 30m K3 K4 K9 K14 K15 I 20m K4 K9 K13 K14 K15 Transisto rS 2SC2166 17m K5 K11 K13 K15 2SC1969 15m K5 K6 K11 K15 ne 2118306 12m K6 K7 K10 K13 K14 K15 iain 10m K7 K10 K13 K15 ZVN4424 MPS5179 J310 60 meters is available only if the K60XV option is installed 40m ALT applies if D19 D20 are not installed NOTE All relays are single coil latching type and are 9 ig B D C e shown in the RESET position in schematics Relay pins 5 and 6 are not connected internally Integrated Circuits PLASTIC DIP VOLTAGE REGULATORS VCO Table DUAL INLINE PACKAGE VCO Freq 78105 06 2930T 8 78XX Band Fixed Cap pF Total Cap pF at band edge 160m C75 470 525 629 6715 subtract FA 80m C72 270 325 429 8415 subtract As IN 60m 71 73 129 215 259 10165 subtract GND 40m ALT 71 73 129 40m 30m 20m 17m 15m 12m 10m C71 120 C734C74 67 C74 20 none 0 C73 47 C74 20 none 0 163 209 154 203 102 131 55 84 35 64 82 111 55 84 35 64 11915 subtract 11915 subtract 14915 subtract 18915 subtract 22915 subt
27. PICTURE Designators Value Description Part Number QTY Appendix A K2 Probe Assemblies Parts List p n E850036 envelope in E850004 Misc bac PICTURE Designators Value Description Part Number QTY FCP C1 10pf cap Axial Leads like a resistor counter probe E530067 1 RFP C1 01 uF cap Monolithic capacitor for optional RF probe E530009 1 RFP D1 1N34A diode For RF probe germanium E560000 1 FCP E1 1 pin male probe tip For counter probe E620044 1 FCP J1 VMP J1 2 pin female housing For counter and voltmeter probes E620021 2 female crimp pins For counter and voltmeter probes E620022 3 Misc Aligator clip insulated For RF probe ground 700074 1 Misc _ plug red For RF probe DMM positive lead E700076 1 Misc plug black For RF probe DMM negative lead E700075 1 RFP R1 4 M Resistor 5 1 4W For RF probe E500048 1 Appendix A K2 Wire Bag Parts List p n E850005 bac PICTURE Designators Value Description Part Number QTY MISC 26 Red Enamel Wire For toroids E 60002 30 ft Misc 26 Green Enamel Wire 760004 8 ft Green solid hookup wire Misc 24 Insulated wire for T4 misc wiring E760008 3 ft White solid hookup Wire Misc 24 Insulated wire for T4 misc wiring 60013 1 ft Black stranded hookup Misc wire 24 For RF probe 760016 6 Misc RG174 Coax Cable For counter and RF probes 760010 3 ft 24 Dual conductor Misc speaker wire For speaker and ext speaker jack E 60012 2 ft
28. an industry standard serial interface protocol used by Philips and other IC manufacturers ELECRAFT Potentiometers R1 R2 and R5 Keyer Speed Power Out and RIT XIT Offset are multiplexed onto a single A to D input of the MCU the VPOTS line so their position can be read Firmware hysteresis is used for these controls to prevent noise from interfering with the readings with more hysteresis on transmit The AF GAIN control is not read by the MCU its leads go directly to the input of the AF amp on the Control Board The entire path from product detector to AF amp is balanced to prevent common mode noise pickup see Control Board for details As 15 true of most modern transceivers the RF GAIN control actually controls the receiver s IF gain it varies the DC control voltage on pin 5 of U12 RF Board The circuitry associated with J2 the mic Jack 15 only present if the SSB option is installed P1 is a configuration header that the user can wire as needed to support any of several industry standard microphones with an 8 pin circular connector Q3 and its associated resistors are used to multiplex the UP DOWN and FUNCTION lines from P1 onto the VPOTS line to allow the mic to send commands to the MCU The PTT line from the MIC activates the DOT PTT line to initiate transmit The MICAF line mic audio output 15 amplified and processed by circuitry on the SSB adapter see Option Modules Control Board The Control board plugs into t
29. harmonic of X1 at about 10 136 MHz while touching a screwdriver blade to pin 7 of U1 NE602 If you can t hear this signal try soldering a 22 k resistor from pin 7 to pin 3 on U1 NE602 If you have the 160 m RXANT option installed make sure you have menu entry rANT setto OFF orif itis ON that you have a receive antenna connected If K60XV option connectors are installed J13 and J15 on RF board but the module 1 removed install C6 and W6 Peak appropriate band pass filters Inspect T R switch components and voltages Trace signal from band pass filters to the antenna using an RF signal generator Make sure the VCO is oscillating on affected bands by using the frequency counter 140 Receiver current drain is too high If you saw the message INFO 140 your receive mode current drain was measured at over 500 mA during normal operation Continue with the checks below Use DISPLAY to show voltage and current on the LCD If the current shown is gt 300 mA with no incoming signal or gt 200 mA with the bargraph turned OFF and no signal you may have a short or excessive load on the 8V or 8R lines 053 Y ou may have the speaker and or external speaker jack wired incorrectly This can place a short across the audio amp output causing very low audio output 1f any and current as high as 500 to 800 mA Transmitter 150 199 Problem 150 General Transmitter problem 155 Power output is low or zero Troubleshooting Steps
30. near the back left corner L Install the following transistors which are located near the I O Controller U1 __ Q10 2N7000 __ PN2222A __ PN2222A 66 Ferrite bead assemblies Z1 and 72 will be installed vertically near transformer T3 as indicated by their component outlines To make these assemblies string two ferrite beads onto a 1 25 mm length of bare hookup wire or discarded component leads as shown in Figure 6 24 Figure 6 24 Install Z1 and Z2 bending the leads on the bottom of the board to hold them in place Make sure that the beads are seated flat against the PC board then solder Locate D9 the 1N5711 diode which you identified and set aside earlier Install D9 near the right edge of the board Install electrolytic capacitors C126 47 uF and C137 100 uF Near the ELECRAFT label at the center of the board Insert the lead of each capacitor into the hole marked Install electrolytic capacitor C125 22 uF which is near Install Q5 2N5109 Be sure Q5 is firmly seated on the board and has its tab oriented as shown by the component outline before soldering ELECRAFT Install the following components on the bottom of board working from left to right __ R63 220 RED RED BRN Note bend the leads of R58 exactly as shown by its component outline __ R58 180 ohms 1 2 watt BRN GRY BRN RFC8 RFC9 _ RFC4 10 uH BRN BLK BLK __ RFC6
31. supplied pre wound and tested this is unlikely The leads of R116 may have been heated excessively during soldering shorting out a portion of L33 s turns One of L33 s leads could be broken Look closely at the leads using a magnifying glass One or more of the capacitors or varactor diodes the BFO circuit could be of the wrong value ELECRAFT BFO Alignment The K2 uses a variable bandwidth crystal filter allowing the operator to set up as many as four filter bandwidths for each operating mode Each of these filter configurations requires an appropriate BFO setting which determines the pitch you hear Filter and BFO set up is done with the CAL FIL calibration function CAL FIL is described in detail in the Operation section of the manual under Calibration Functions Rather than duplicate this information here we ll refer you to the instructions and example in the Operation section Make sure the bottom cover 15 securely attached Tap until the PRE annunciator is turned on Turning the preamp on will provide some background noise so you can hear the effect of changing filter bandwidths Follow all instructions page 88 to become familiar with CAL FIL function Perform the steps in the example on page 89 to set up all filters You ll use the filter and BFO data from Table 8 1 for a CW only K2 since the SSB adapter 1 not installed If you later install the
32. switching fixed capacitors in or out using two additional relays For example on 160 meters relay places C13 and C14 across the 80 m band pass filter But relay K3 also used to switch the 20 meter band pass filter to 30 meters by shorting C21 and C23 to ground K6 places C32 C34 across the 15 m inductors to select 17 meters or C44 C46 across the 10 m inductors to select 12 meters The band pass response is a compromise on 80 and 160 meters but on all other bands is similar to what would be obtained with separate filters The low pass filters also serve double duty in most cases five filters cover 8 bands 80 10 m The 30 20 m filter uses three pi sections to provide good roll off of the 20 MHz second harmonic when operating on 30 meters Most of the filters are elliptic aiding attenuation of specific harmonics But elliptic filters are not needed on 40 and 80 meters since these each cover only one band The 2 harmonic attenuation provided by the push pull power amplifier is quite good even pre filter sheet 4 DPDT relays are used for the low pass and band pass filters rather than the traditional SPDT approach which requires twice as many relays This is possible by virtue of careful guard banding techniques on both top and bottom of the PC board in the filter areas Isolation between input and output of each filter 15 excellent across the entire frequency range The switch 01 05 provides very high isolation using low cost sili
33. the transceiver will function normally even when running from very depleted batteries most transceivers use a higher regulated voltage for these stages and in some cases will not operate reliably even at a battery voltage of 11 V Transmit power will be scaled back and a warning message displayed if the battery voltage drops below a critical value or if current drain is excessive U5 provides 5 V for logic circuits on the front panel and Control board but this signal does not appear on the RF board so noise is minimized 8 V Switching and Q2 provide stable 8 V sources on transmit 8T and receive 8R 023 on the RF board is used to guarantee that SR goes to 0 V on receive to maintain proper reverse voltage on T R switch diodes An optional audio filter module KAF2 or KDSP2 can be mounted on the bottom of the Control board These options provide analog or digital filtering functions The audio filter module has its own co processor Q6 and Q7 disconnect the AF amplifier from the product detector on transmit which is necessary for clean QSK U9 is an LM380 audio amp IC supplying approximately 1W of audio drive to a 4 ohm speaker in the cover ELECRAFT of the K2 Sidetone is injected post volume control so that sidetone and receiver audio volume can be controlled independently The AGC circuit is the only RF stage located on the Control board Mixer oscillator U1 generates low level signal at about 5 068 MHz then mixes
34. 0 1 104 7 C16 047 473 01 103 7 CI9 047 473 C21 33 33 C23 01 103 C43 001 102 C26 0 1 104 C20 001 102 C27 022 223 24 0027 272 C24 001 102 C30 047 473 C35 01 103 C36 0027 272 C41 01 103 C37 01 103 CI8 01 103 C25 0 1 104 C31 01 103 C40 01 103 C39 01 103 7 C38 680 681 Solder all of the small fixed capacitors 15 Install and solder the electrolytic capacitors listed below which are polarized Be sure that the lead 1s installed in the hole marked with a symbol The lead is usually longer than the lead and the lead 15 identified by a black stripe Figure 4 1 Figure 4 1 CL22uF 13 22 C15 100 uF 2 C28 220 uF C29 220 uF 2 2 2 uF 32 22 Install and solder ceramic trimmer capacitor C22 Orient flat side of this trimmer as shown on its PC board outline n Using a small flat blade screwdriver set C22 so that its screwdriver slot 1 parallel to the outline of nearby crystal X2 Locate 012 type PN2222A which is a small black TO 92 package transistor Q12 and other TO 92 transistors may have either of the two shapes shown in Figure 4 2 The large flat side of the device must be aligned with the flat side of the component outline The part number may be found on either si
35. 2 5 seconds for slower CW work or to prevent un muting when sending a repeating beacon message ELECRAFT The SPOT Switch The switch can be used to zero in on received signals or to test your sidetone pitch quickly without having to key the transmitter or enter the menu It s important to use before using CW reverse Once a signal has been SPOTted you ll only hear a slight change in pitch when you use the switch When you use 5298 receiver audio will not be muted This allows you to listen to another station and turn the VFO knob until the pitch of the received signal matches that of the sidetone Once the two match you ll be very close to the station s frequency if you call Exception If you re using RIT or your transmit and receive frequencies will differ by more than just the normal transmit receive offset Turn off these features when using 8 Matching audio pitch may be difficult for some operators Basically you ll need to tune the VFO up and down until the station you re hearing seems to disappear under the sidetone that 1s until you can t hear any difference between the two When this happens you ll know the two pitches are matched Using the Internal Keyer Two menu entries are provided to set up the keyer allows you to select Iambic mode or B Mode A 15 similar to Curtis mode A mode B is similar to Super CMOS Keyer III mode B If you aren t sure which
36. Aux AF T7 R107 OO 1 100K X6 X5 D29 D34 1SV149 2 R110 180 L 4 C181 RU 01 D39 I F OUT 179 MV209 411 SSB Control ae C183 2nd Xtal Filter 01 EN X3 XFIL In XFIL Out nas C173 100K 4 917MH 220 C186 PN2222A 2 01 X4 5 EXT ALC x BFO RP6 poe Q24 ah 100K 270 C168 p a 9 NZ 1SV149 TEN 01 4 3 C167 001 NOTE 1 d 5 D37 RP6 C172 S a 390 NOTE 1 Remove C167 when SSB Adapter is installed 25 Ese TP2 L 6 APS NOTE 2 D40 and D41 were added to improve handling of extremely 270 5082 3081 100K strong signals from nearby transmitters These diodes V7 must be soldered on the back of the PC board see text Elecraft K2 RF Board BFO Buffer Attenuator By W Burdick Rev Date Sht E Swartz F 1 27 04 2 Appendix B Xverter 7 Interface C7 100 100 L2 C4 C8 n 2 820 4 7uH 820 9 8R 40 60m M ees P6 L5 01 j RXRY RY COM gee C13 C14 1200 5 4 80 160 16 RFC2 1868 9 100 1N4007 C114 L4 K2B 24 04 01 W1 A L16 80m 117 e 4 7uH P Q RX Ant C190 C191 C192 1N4007 Bras Bypass 2 1200 1200 9 W6 47uH XVTR 1N4007 20 24 T ore L9 Bypass 20 30m 4 7uH 4 7uH pen 4 a 20 30m 47 7 G M S C113 C19 C28 C29 01 3 C25 8 330Z c21 T 1
37. C26 C42 a Hei Cas ir lm C21 NPO disc cap 33 or 330 see page 9 1 Sj 2 3 2 Ceramic trim cap Green paint screw with RED Marking on side or no markings C22 var 8 50pF at all E540000 1 D1 D2 1N4148 Silicon switching diode small glass body E560002 2 1N5817 Shottky diode black body 560008 1 82 mH inductor 5 Shielded cylindrical dark gray E690015 1 Page 1 Control Appendix K2 Control Board Parts List p n 50002 PICTURE Designators Value Part Number QTY Description O 79 3 co D ZU 2 Right Angle 6 pin connector Right Angle 18 x 2 pin connector Right Angle 10 x 2 pin connector 5 X 2 pin connector for Aux gt NO 3 D D EU gt 2 Includes locking ramp for Volt Meter Freq Counter Inputs P5 P6 E620024 2 P3 E620041 h voltmeter source selection 1 2 3 2 011 012 2 1 1 R10 1 R9 1 R18 R19 2 R20 R16 1 R6 100 5 TAN 1 R12 1 R4 1 R3 1 R5 1 R11 1 R22 1 R21 1 R2 R17 3 3M 5 7 2 2 Control Appendix K2 Control Board Parts List p n 50002 PICTURE Designators Value Description Part Number QTY 527 24 R1 SOK Trimmer AGC Threshold E520011 1 5 471 770103471 510015 1 3 9K OR ISO SIP resistor pack 10 pins ALT RP1 770103392 10A3
38. CAL PLL and CAL FIL before operating the K2 otherwise the VFO cannot be tuned properly and the synthesizer may not be locked see Operation as well as RF board Alignment and Test Part IT Make sure the supply voltage is above 8 5V at all times or the 8V regulator may not function correctly If you used solder with water soluble flux you may have conductive paths all over the PC boards These can cause numerous problems with the VFO BFO and logic circuits anything high impedance Try cleaning the entire board with hot water and a Q tip or follow solder manufacturer s recommendations except immersion If you used CAL FIL to change the BFO settings make sure you placed the BFO on the correct side of the zero pitch value for each operating mode see Operation Filter Settings If you tune beyond the lock range of the VCO the frequency will stop changing and may hunt near the end of this range If you are in a range that the VCO should be capable of tuning re check VCO alignment see RF board Alignment and Test Part IT If the displayed frequency is garbage see Resetting the Configuration to Defaults in Advanced Operating Features Control Circuits 050 099 Problem 050 Regulated voltage s incorrect 051 General problem with control circuits switches knobs display bargraph T R switching 052 5V too low lt 4 75V Troubleshooting Steps Remove all option boards since any one of them might be
39. Carefully strip and tin leads of T5 s 1 2 winding ELECRAFT L T5 s other winding 3 4 uses 4 turns of green enamel wire 7 18 cm Wind the 3 4 winding on top of the 1 2 winding interleaving the turns as shown in Figure 6 16 The turns should be secure not loose Strip and tin the leads of the 3 4 winding Note T5 s 3 4 winding must be wound exactly as illustrated or the VFO will not function correctly Figure 6 16 Install T5 as shown by its component outline in the synthesizer area of the board Figure 6 17 shows how the 1 2 and 3 4 windings are oriented with the numbered pads Also shown are the nylon washer and screw which will be installed in the next step Pull T5 s leads taut on the bottom of the board but do not solder yet Secure T5 to the board as shown in Figure 6 17 using a 3 8 9 5 mm diameter nylon washer 1 2 12 7 mm long nylon 4 40 screw and a 4 nylon nut Tighten the nylon nut just enough to hold the assembly in place Do not over tighten as this will strip the threads Solder T5 checking for good solder joints as before 55 Ly 2 2 4 Figure 6 17 T7 is a toroidal transformer wound on a 3 8 9 5 mm diameter ferrite core dark gray FT37 43 T7 s orientation and windings will appear similar to Figure 6 18 Wind T7 s 3 4 winding first using 20 turns of red enamel wire 20 51 em The drawing shows 14 turns Wind T7 s 1 2 win
40. Figure 5 2 ELECRAFT Top of board 1 16 Figure 5 3 Figure 5 3 shows a side view of a switch that is properly mounted spacing tool not shown The leads of the switches will just be visible on the bottom of the board Proper switch height is important for maintaining an even appearance Once you re satisfied that S1 and 52 are seated correctly solder the leads on the bottom side of the board Leave the spacing tool in place until you ve finished soldering both switches L Install the remaining switches S3 S16 using the same technique When you get to S8 through S16 you may install three switches at a time using the spacing tool Install the following 1 4 watt fixed resistors which are listed in left to right PC board order Solder the resistors after all have been installed R13 and a few other parts are part of the SSB adapter option and are not included in the basic K2 kit A check list of these components is provided at the end of this section __ R12 120 BRN RED BRN R10 33 ORG ORG BLK 9 220 RED RED BRN R11 470 YEL VIO BRN 4 7 YEL VIO RED R7 4 7 k YEL VIO RED R14 100 BRN BLK YEL LJ Install the following resistors on the bottom of the board Solder them on the bottom side Keep your iron tip away from the bodies of the resistors 2 R16 15k BRN GRN ORG R15 10 BRN BLK ORG 23 AN When you install the resistor networks in the next step
41. Iambic A and B adjustable weight 9 50 WPM 9 buffers of 250 bytes each 1 level chaining auto repeat 0 255 s For reference only not guaranteed If higher power than shown here is to be used for a given supply voltage monitor transmitter output signal Receiver Sensitivity MDS 3 order intercept 214 order intercept Dynamic range Blocking Two tone Selectivity CW SsB Audio output Speaker Headphones Varies with band ELECRAFT Preamp On Preamp Off 135 dBm 130 dBm 0 to 7 5 10 70 70 125 dB 133 dB 96 97 4 915 MHz single conversion 7 pole variable bandwidth crystal filter approx 200 2000 Hz 7 pole fixed bandwidth crystal filter 2 2 kHz typ watt max into 4 ohm load internal 4 ohm 3 W Rear panel jack for external speaker 4 32 ohms stereo or mono With optional SSB adapter Other CW and SSB fixed crystal filter options may be available ELECRAFT 3 Preparation for Assembly Overview of the Kit The K2 uses modular construction both physically and electrically This concept extends to the chassis Figure 3 1 Any chassis element can be removed during assembly or troubleshooting Also see photos in Appendix D If the KPA100 is installed it takes the place of the original top cover Top Cover Bottom Cover Right side panel not shown Figure 3 1 As shown in Figure 3 2 there are three printed circuit boards PCBs
42. K2 kit includes a complete RF probe including the PC board coax and connectors The switch spacing tool which you used in assembling the Front Panel doubles as the PC board for the probe The RF probe Figure 1 converts RF signals to DC so they can be measured using a DMM The DC readings on your DMM will be approximately equal to the signal voltage in Vrms root mean square C1 R 1 COAX B 4 7 24 60 1 ps E2 To DMM ground Figure 1 Assembly Instructions Use a discarded lead from a large diode such as an SB530 or 9550015 as the probe tip It should be about 1 2 5 cm long All other components for the probe can be found in the MISCELLANEOUS bag An insulated alligator clip is provided for ground E2 It should be connected to the board using 4 of black insulated hookup wire Two banana plugs are supplied for connecting the probe to your DMM P1 P2 Use RG174 coax between the probe board and the banana plugs The coax should be secured to the board using one cable tie Thread the cable tie through the two holes provided near the coax end of the board To use the Probe Connect E2 to the nearest ground test point and plug the banana jacks into your DMM Set the DMM for DC volts 20 or 30 V scale Avoid touching the tip or discrete components while taking measurements Signal Generator A simple crystal oscillator Figure 2 can be used in lieu of a signal generator
43. LF derived AGC with fast slow off control full break in operation with no relays accurate control of sidetone volume and sidetone pitch offset memory keyer with Iambic modes A and B nine programmable message buffers chaining and auto repeat software selectable paddle selection normal or reverse multiple crystal filter bandwidths and opposite sideband CW dedicated switch for accurate signal pitch matching optional analog or digital audio filter Several advanced CW features are covered in later sections Fast Play one touch message buffers page 103 Adjustable keying weight page 103 smart CW signal scanning page 99 FINE RIT for fine tuning CW signals page 102 Keying Device Selection A single connector in the back is provided for your keyer paddle hand key keyer or computer It is also possible to connect both a paddle and an external keyer or computer at the same time see External Keying Auto Detect below You must use a stereo 2 circuit plug even if you use only a hand key or external keyer This should not affect the use of the keying device with other equipment since the middle contact on the plug often called the ring contact is only used with keyer paddles Hand key or External Keying Device To use a hand key or external keying device select INP HAND using the menu Use the tip contact DOT of the key jack with a hand key or external keying device You can key the K2 externally at up to 70
44. Oscillator Calibration After setting C22 using either technique you must re run CAL PLL with the counter probe on TP1 You ll also need to use CAL FIL with the probe on TP2 to re adjust each BFO setting which will allow the K2 to store new more accurate BFO frequency measurements Using a Calibrated Signal Source You can calibrate C22 using a signal generator ham transmitter or strong AM carrier such as WWV at 10 MHz The K2 s receiver is used to zero beat this signal to determine how far off the VFO 1s then C22 15 adjusted to compensate Here s the procedure 1 Select LSB or USB mode on the K2 Zero beat the calibrated signal source on the K2 then note the VFO dial error For example 10 MHz WWV might zero beat at 10000 20 kHz The error is then 10000 20 10000 00 0 20 Do not move the VFO from this position 3 Connect the K2 s internal counter to the VCO test point TP 1 4 Select and activate CAL FCTR using the menu 5 Note the displayed VCO frequency In this example 14913 88 kHz Your VCO frequency will be somewhat different 6 Subtract the VFO dial error from the VCO to obtain a target VCO frequency In our example 14913 88 0 20 14913 68 7 Adjust C22 until the VCO is at the target frequency 8 Re run CAL PLL see Calibration Functions Tap MENU to exit CAL PLL when End appears 9 Move the counter probe to TP2 BFO Using CAL FIL change the BFO control parameter for the filter presentl
45. R9 R16 R17 R21 R37 R69 TAN 5 1 4 watt l R18 E500024T 1 R22 33M OEA 100K 3R ISO 6A3 104 SIP resistor pack 6 pins ALT 77063104 510017 2 100K 4R ISO 8A3 SIP resistor pack 8 pins ALT 77083104 104G or B104G 1 0 10K 4R ISO 8A3 103G SIP resistor pack 8 pins ALT 77083103 E510005 1 TP1 TP2 TP3 test point female E620036 3 Relay Driver PIC I O Controller 16F872 programmed TI TI TI O O Ql O O O O O O O O O N 78LO6AWC TO 92 6v Reg For relays Page 8 RF Appendix K2 RF Board Parts List p n E850001A and E850001B PICTURE Designators Value Description Part Number QTY U3 U9 LT1252 8 pin DIP VFO Buffer TX Buffer E600020 2 8 pin DIP 12 Bit DAC for Reference Freq 010 077 2 NS 78L05 5 volt reg 100mA E600029 MC145170P2 orP1 16 pin DIP PLL E600016 1 W1 W2 W3 W5 W6 Use component leads X1 X2 not used 12096 kHz PLL reference oscillator crystal HC 49 E850007 1 BFO crystals matched set HC 49 4915 2 kHz Typical labeling ECS D 4 91 S E850008 2 Filter crystals matched set HC 49 X5 X6 X7 X8 X9 X10 X11 4913 6 kHz Typical labeling ECS V 4 9136 E850006 7 4 000MHz Resonator Ceramic resonator w caps 0 2 tolerance E660001 1 TUF 1 or TOP 1 Balanced diode mixer E980025 1 Page 9 RF Appendix 2 RF Board Parts List p n E850001A a
46. RF board is used to peak the output of the I F amplifier Using the wide end of the plastic tuning tool adjust the slug in 134 until it is near the top of the can Stop turning the slug when it appears to be at the top or when you feel resistance Turn L34 s slug one full turn clockwise down into the can Set the band to 40 meters using or Select CW Normal and FL2 700 Hz nominal bandwidth Make sure the RF GAIN control is fully clockwise max gain Disconnect the antenna from J4 if one was connected until PRE annunciator turns on Connect a pair of headphones stereo or mono to the front panel jack and turn the AF GAIN control to about midway Slowly tune the VFO to locate the weak internally generated signal near 7000 kHz If you can t hear the signal at all you may have a receiver problem Try the 40 meter Band Pass Filter Alignment below then refer to Troubleshooting if necessary While listening to the signal at 7000 kHz adjust L34 for best signal strength and lowest noise This setting occurs at about 1 to 1 5 turns below the top of the can You can use your DMM on AC volts at the speaker jack to obtain a more sensitive indication 40 Meter Band Pass Filter Alignment Connect an antenna or a signal generator to the antenna jack on the rear panel If you use a signal generator set it for appro
47. about 10 and connect a pair of headphones Switch to the 30 m or the correct band for your signal generator Connect a signal generator or test oscillator to the antenna jack Set the signal generator for 0 14 Vrms as indicated by the RF probe If possible tune the VFO until you hear the signal It may be quite strong even if your receiver is attenuating the signal somewhere Find the approximate signal peak by ear Set AF GAIN to minimum Align the band pass filter for the current band if possible a Put the RF probe on the banded end cathode of D6 to the left of the I O controller U1 b adjust the band pass filter for the current band for a peak indication on the DMM on 30 m adjust L8 and L9 Aligning the band pass filter may have changed the input impedance of the receiver Put the RF probe back on the antenna input and adjust the signal generator for 0 14 Vrms again Low Pass Filter Output Measure the signal at jumper W1 near the PA transistors Q7 Q8 Expected 0 13 Vrms Actual T R Switch 1 Output Measure the signal at W6 which is is to the right of the transverter 60 meter option connector J13 near the back edge of the board Expected 093 Vrms Actual Band Pass Filter Output Measure the signal at the left ade of D6 Expected 086 Vrms Actual Switch 2 Output Measure the signal at the right side of D6 Expected 077 Vrms Actual 11 Mixer Amplifiers and Crystal Filter shee
48. also tap the or BAND switches to scroll through menu entries Scroll the menu until you see INP HAND This menu entry is used to select the keying device HAND means that the key jack 1 configured for a hand key or external keyer Press and hold the switch for 1 2 second to activate the EDIT function Remember the TAP HOLD rule when you HOLD a switch in you activate the function indicated by the lower label on the switch The display should now show INP HAND Notice that the underline has moved to the parameter HAND This tells you that you re in EDIT mode and that turning the VFO knob will now change the parameter for the current menu entry You can also change the parameter using and Turn the VFO knob now to see the various keying input selections PDLn and PDLr configure the key jack for a keyer paddle wired for either normal tip dot or reverse tip dash operation Tap the MENU switch again to exit EDIT mode The underline should return to the menu entry ELECRAFT Using the Calibration Functions Scroll the menu until you see CAL OFF This is the entry point into the calibration sub menu which you ll be using during alignment Enter EDIT mode by holding as before moving the underline to the OFF parameter Then turn the VFO knob to see the various CAL functions including FCTR frequency counter CUR transmit current limiting tPA
49. and 4918 kHz AN If you see a reading of 0000 00 kHz or one that is changing rapidly you may not have the frequency counter probe connected properly or the BFO may not be working see Troubleshooting If you see a stable frequency reading that 1s nowhere near 4908 4918 kHz you may have installed the wrong crystals in the BFO X3 X4 When you re in frequency counter mode the B AND and B AND switches be used to check the range of the BFO First tap and write down the frequency reading below typically about 4916 4917 kHz Then tap BAND and write down this frequency reading usually about 4909 4912 kHz Finally calculate the BFO range high low in kHz Typical range is 4 to 6 kHz BFO High Freq must be gt 4916 3 kHz BFO Low Freq must be lt 4912 7 kHz Range High Low must be gt 3 6 kHz ELECRAFT If your BFO range 15 less than 3 6 kHz you may have the wrong varactor diodes installed at D37 or D38 or the wrong crystals installed at X3 or X4 If the BFO frequencies are shifted too high or too low it may be due to one of the following If you didn t calibrate the K2 s internal frequency counter using an external counter it may not be reading accurately If possible borrow an accurate counter and re do the 4 MHz Oscillator Calibration The BFO range shift could be due to the inductance of 133 being too high or too low However since L33 1
50. and UHF transverters For a complete description of available options see page 113 In addition to the options a companion enclosure the same size and style as the K2 is available for those who wish to build their own matching station accessories model EC2 The K2 is an intermediate level kit yet you ll be pleasantly surprised at how uncomplicated it 1s to build All of the RF radio frequency circuitry is contained on a single board while two plug in modules provide front panel and control functions Wiring 1s minimal unlike traditional kits which depend on complex wiring harnesses A unique feature of the K2 1 that it provides its own built in test equipment including a digital voltmeter ammeter wattmeter complete RF probe and frequency counter These circuits are completed early in assembly so they re ready to be used when you begin construction and alignment of the RF board We also provide complete troubleshooting and signal tracing information In addition to this owner s manual you ll find extensive support for the K2 on our website www elecraft com Among the available materials are manual updates application notes photographs and information on new products There s also an e mail forum sign up is available from the web page It s a great way to seek advice from the K2 s designers and your fellow builders or to tell us about your first QSO using the K2 We d like to thank you for choosing the K2 transceiver
51. as shown in the edge view Figure 5 11 If the LCD does not appear to be seated correctly it may be because the backlight LEDs or spacers are mis aligned When the assembly 15 installed correctly the LCD s pins will all protrude the same distance from the bottom of the board Some units may be supplied with shorter pins that do not protrude at all Solder the four corner pins of the LCD then re check the alignment of the LCD assembly If everything looks correct solder the remaining pins LCD pins can be soldered on the top of the board if they do not protrude from the bottom Attach two thin 1 4 6 4 mm self adhesive rubber pads to the bottom side of the Front Panel board in the positions indicated in Figure 5 12 The pads should be placed as close as possible to the corners but should not hang over on either edge These pads establish the correct spacing for the Front Panel board Top Edge Bottom of PC Board Figure 5 12 28 Uninstalled Components Check off each of the components in the list below verifying that they are not yet installed C4 01 103 C7 01 103 __ C5 01 103 7 C8 01 103 01 103 R13 68 1 __ RP3 lO resistor network __ 2N3906 __ Mic Configuration connector on the bottom of the board The unfilled locations above are for parts that are provided with the SSB adapter model KSB2 If you have the SS
52. below Identifying Capacitors Small value fixed capacitors are usually marked with one two or three digits and no decimal point If one or two digits are used that is always the value in picofarads pF If there are three digits the third digit is a multiplier For example a capacitor marked 151 would be 150 pF 15 with a multiplier of 10 Similarly 330 would be 33 pF and 102 would be 1000 pF or 001 uF In rare cases a capacitor manufacturer may use 0 as a decimal placeholder For example 820 might mean 820 pF rather than the usual 82 pF Such exceptions are usually covered in the parts lists To be safe measure the values of all capacitors below 1000 pF most DMMs include capacitance measurement capability Fixed capacitors with values of 1000 pF or higher generally use a decimal point in the value such as 001 or 02 This is the value in microfarads uF Capacitors also may have a suffix after the value such as 001J In some cases the suffixes or other supplemental markings may be useful in identifying capacitors Hard to identify capacitor values 3 3 pF These capacitors may have pillow shaped dark green bodies about 1 8 3 mm square with a black mark on the top The 3 3 label may be difficult to read without a magnifying glass 150 pF These are correctly marked 151 on one side but the other side may be marked 21 ASD where 21 looks like 821 10 Resistors Chokes and the Color Code
53. board and seated as far down on the board as it will go exactly 1 8 3 mm above the board Solder D2 and D3 If the backlight assembly is not flat against the PC board re heat the LED pins one at a time and press it into place AN CAUTION The LCD and its pins are fragile handle carefully Do not drop the LCD on a hard surface as it is made of glass and may break Do not remove the protective plastic film from the front surface of the LCD until later in this section when the front panel assembly 1 completed Carefully remove the LCD from its packing materials AN CAUTION Do not peel off the thick plastic material on either side of the LCD or the LCD will have to be replaced not covered under warranty Hold the LCD up to a bright light and look at both sides for the presence of a very thin clear protective film like transparent tape All LCDs have such film on the front surface of the LCD which will be removed in a later step But the back of some LCDs not all may also have such film with faintly visible yellow or gray diagonal lines If protective film 15 found on the back side use a fingernail at one corner of the LCD to dislodge it then peel it away The LCD has six pins along its lower edge three on each side and 24 pins along the upper edge Place the LCD in its proper position on the board but do not solder yet 27 LCD Figure 5 11 The LCD must be seated flat against the diffuser
54. board using 4 chassis screws Refer to the photos in Appendix D You may need to make slight adjustments to the 2 D fasteners at the top edge Figure 6 10 ELECRAFT Plug Control board assembly into RF board with component side of the Control board facing backwards Refer to the photos in Appendix D All three connectors on the Control board must be lined up with the three connectors on the RF board at all pins Make sure the Control board is pushed as far down as it will go it should be flat against the RF board along its entire edge with all three connectors properly mated AN If the Control board does not plug in easily you may have one or more connectors installed incorrectly The long handled Allen wrench can be used to extract the Control board Figure 6 11 To the left of J7 on the RF board you ll find the label LIFT near a hole at the base of the Control board Insert the Allen wrench into this hole then rest the knee of the wrench on the nearby screw head Pry the board up with the wrench while guiding the board out at the top Long handled allen wrench Figure 6 11 41 Once you have tried Control board extraction technique described above plug the Control board back in for the tests that follow Secure the front panel and Control boards together using two chassis screws Figure 6 12 The upper left and right corners of the Control board may be touchi
55. but should have different markings Use a piece of masking tape to identify 1N5711 as D9 1N5711 Install the following diodes located near the outline for toroidal transformer T5 in the synthesizer area Be sure to orient the diodes according to their outlines IN4148 D6 IN4007 D13 154148 IN4007 Varactor diodes have a small plastic package like a TO 92 transistor but with only two leads Sort the varactor diodes into groups type MV209 and type 1SV149 18V 149 diodes are labeled V149 and may have a center lead that has been cut flush with the body of the device The K2 will not function correctly if the varactor diode types are interchanged Install the MV209 diodes listed below The flat side of each diode must match the flat side of its PC board outline These diodes must be pushed all the way down on the board to prevent stray signal coupling Bend the leads slightly to hold them in place D16 and 023 026 are in the front left corner D39 is to the right of J7 Control board 216 p23 __ 224 25 _ D26 D39 Note Do not install 019 and 020 These are supplied with the K60XV option which should not be installed until the K2 has been aligned and tested Install type ISV149 diodes at D37 and D38 near the SSB option connector Keep them flat against the PC board with no excess lead length ELECRAFT Install remaining 1SV149 diodes listed bel
56. chances are it is not making good contact Measure from pad to pad not wire to wire using an ohmmeter to be sure the leads are making contact ELECRAFT AN Do not use adhesives or fixatives of any kind to secure toroids to the PC board Toroids will be adequately held to the board by their leads alone T5 15 the only exception RFC16 is wound an FT37 43 core dark gray using 16 turns of red enamel wire 12 30 cm Wind this inductor in the same manner as RFC14 Install RFC16 vertically to the right of RFC14 is wound on FT37 43 core using 20 turns of red enamel wire 16 40 cm Wind this inductor and prepare its leads in the same manner as 4 L Install RFC11 horizontally on the bottom side of the board as shown by its component outline near the center of the board The pads for RFC11 are the two that just touch the outline Pull the leads taut on the top to keep the toroid secured to the board then solder AN T5 1s a toroidal transformer with two numbered windings These numbers are printed next to each pad on the PC board T5 s windings are 1 2 and 3 4 Locate large yellow core T50 6 for use at T5 The core is 1 2 12 7 mm in diameter LJ Wind the first winding 1 2 using 16 turns of red enamel wire 15 38 cm This winding must occupy 85 of the core and will look very similar to Figure 6 15 Remember that each pass through the core counts as one turn
57. coax and cause a shield to center short Insert the pins into the crimp housing as shown in Figure 6 14 They should snap into place Each crimp pin has a small tab on the back that latches into a hole in the housing Trim leads of 10 pF axial lead capacitor down to 1 4 6 mm Solder one end to the center conductor of the coax cable RG 174 Coax 1 10pF 7 18cm Heat shrink tubing 2 layers Crimp housing Figure 6 14 Solder probe tip to other end of 10 pF capacitor Slip a 1 2 5 cm length of the larger size heatshrink tubing onto the probe tip components Shrink the tubing using a heat gun You can also use a soldering iron but avoid melting the tubing Add a second identical length of heatshrink tubing on top of the first then shrink it This strengthens the assembly 46 Plug frequency counter probe assembly into P6 which is at the far left end of the Control board as viewed from the front of the transceiver The connector can only be plugged in one way Turn on the K2 and tap MENU to bring up the menu then scroll to the CAL menu entry Hold then scroll the CAL parameter until the display shows CAL FCTR Hold again to activate the frequency counter function of the CAL sub menu The LCD should show 00000 00 The frequency counter circuitry is sensitive so it may pick up a stray signal and show it on the display T
58. control of the K2 and uses true RS232 signal levels It works with most transceiver control and logging software as well as our own k2remote and k2voice programs KDSP2 or KAF2 Audio Filter and Real Time Clock The KDSP2 provides advanced DSP filtering auto notch and noise reduction The KAF2 provides analog low pass and narrow CW band pass functions Both include time date display and an on board long life backup battery KPA100 Internal 100 Watt Stage with RS232 I O The KPA100 completes the K2 as a 100 W PEP CW transceiver The kit comes with its own top cover heat sink that replaces the K2 s original top cover The original top cover can be re installed in about one minute for lightweight field operation KRC2 Programmable Band Decoder The KRC2 can be used to control antennas amplifiers transverters filters or other station equipment directly from the K2 Custom configuration 1 possible using a PC XV Series Transverters Elecraft s transverters are an ideal match for the K2 providing high performance receive and 20 25 watts output on VHF UHF bands The K2 can directly control up to six transverters Appendix K2 Packing Box Parts List PICTURE Part Number QTY Pci Board RF Chassis piece painted E100076L 1 Rontpans Chess painedisiicscreene Bb Chassis piece painted __ Bag Wie Pack _ Wwecomwhesshikubng 855 Bag Front Panel Pars FmniPandbomdp
59. for BAR Receive performance is minimally affected by this setting unless you have very strong in band stations nearby LCD to DAY to turn off the LCD backlight This is most effective if you also set GRPH to OFF since each bargraph LED segment that is turned on in DAY mode uses about 18 mA Each segment uses only 6 mA in NITE mode Note Voltage current display mode can be used to verify the effect of each setting Using a Separate Receive Antenna The 160 m RXANT option K160RX provides a separate receive antenna which can be enabled on a pre band basis To enable the receive antenna Switch to the desired band Use the menu to change the RANT option to ON The preamp and attenuator settings with RANT ON can be set independently from of their normal settings If you switch between the normal and receive antennas often you can program or as RANT and it will switch immediately one switch press ELECRAFT Programmable Function Switches PF 1 PF 2 The zl and 957 switches below and respectively be programmed as direct edit shortcuts to any two menu entries of your choice including secondary menu entries see page 103 Two special functions can also be assigned to 2 Fast Play FPon page 103 and SCAN RESUME SCAN page 99 To program 291 or 2 Enter the menu and scroll to PF1 PF2 then change the parameter to the desired entry Exit the menu To us
60. holes on one edge of the board are used as leads to insert into the pads provided for the original resistor network RP3 Solder one wire into each of the holes with most of the lead protruding from the component side On the component side bend each lead at a 90 degree angle so that it points away from the board but parallel to it Locate the position for resistor network RP3 near the front left corner adjacent to U6 Slide each of the 8 leads of the thermistor board through the corresponding holes at RP3 The components on the thermistor board should be facing U6 and the thermistor should be oriented toward the location of crystal X1 See Figure 6 14a Figure 6 14a L Once all of the leads are inserted slide the board down until it is flush against the RF Board It may be necessary to bend the thermistor board toward U6 slightly so that the solder joints on the bottom of the thermistor board can clear C87 on the RF board The thermistor board and its parts should not be touching U6 or its pads Make sure the edge of the thermistor board 15 contacting the RF Board along its full length Then solder the eight connections on the bottom side of the RF Board Examine the area closely There should be no shorts between the thermistor board and nearby components 50 Locate all of the small glass bodied diodes You should have a number of 1N4148 diodes and one 1N5711 which will be similar in size
61. in the basic K2 kit the Front Panel board Control Board and RF board Option modules plug into the RF or Control board but are not shown here Front Panel Figure 3 2 ELECRAFT Board to board Connectors The circuit boards in the K2 are interconnected using board to board connectors which eliminates nearly all hand wiring Gold plated contacts are used on these connectors for reliability and corrosion resistance Figure 3 3 shows a side view of the PC boards and board to board connectors As can be seen in the drawing the Front Panel board has a connector J1 which mates with right angle connector P1 on the RF board Similarly right angle connector P1 on the Control Board mates with J6 on the RF board Not shown in this drawing are two additional right angle connectors on the Control board P2 and P3 which mate with J7 and J8 on the RF board These multi pin connectors are very difficult to remove once soldered in place Refer to Figure 3 3 during assembly to make sure you have each connector placed correctly before soldering Front Panel Control Board PI RF Board J6 gt Figure 3 3 ELECRAFT There are six steps in the K2 assembly process Control Board assembly Front Panel Board assembly RF Board assembly and test part I control circuits RF Board assembly and test part II receiver and synthesizer RF Board assembly and test part transmitter Final assembly This a
62. is 9 turns of red enamel wire 10 25 cm The 3 4 winding 1 3 turns of green enamel wire 5 13 cm The drawing shows more than 9 turns on the larger winding Prepare T1 s leads as in Part II Completely remove the insulation to within about 1 8 3 mm of the core then tin the leads nd F3 T Figure 6 25 Install 1 horizontally near Q5 inserting the leads into the matching numbered holes as indicated by the above illustration and by the component outline 68 T2 1s wound on the same core type as 1 FT37 43 Its windings must be spaced as shown in Figure 6 26 a with the 3 4 winding occupying about half the diameter of the core T2 s 1 2 winding is 12 turns of red enamel wire 13 33 cm and its 3 4 winding 1 8 turns of green 9 23 cm Prepare T2 s leads but leave an extra 1 2 of insulation on leads 3 and 4 green as shown in Figure 6 26 a Fold the leads of T2 s green winding 3 4 down and under the core as shown in Figure 6 26 b Install T2 horizontally just to the right of Q6 To ensure that the leads do not contact any adjacent pads or components T2 should be mounted so that it 15 elevated slightly above the board about 1 16 1 5 mm uz 3 AU gQ 4 nS i 9 Figure 6 26 Transformer T3 is mounted vertically to the right of T2 The wires for the two windings must be twisted together before winding bi filar First cut two 10 25 em
63. it You ll hear the shape or pitch of the noise change Return to the original bandwidth after experimenting The number shown should be used only as a relative indication of filter bandwidth Actual bandwidth will probably be narrower ELECRAFT BFO Displays Tap B AND to display the BFO setting for filter FL1 which will be similar to BF1t110c The 3 digit number is the BFO control parameter This number can be changed using the VFO knob but you ll use a different BFO setting method described below The letter t after BF1 is a reminder that the BF1 BFO frequency is always used on transmit which is important for SSB operation Whenever the BFO control parameter is displayed you can tap DISPLAY to show the actual BFO frequency in kHz The VFO knob can then be used to set the BFO directly This method 1s used in the filter setup example Note After changing the BFO setting you tap to re measure and save the BFO information without switching filters This is useful if you want to try various BFO settings for a particular filter to find the one with the best audio peak Other CAL FIL Operations When you re in CAL FIL you can always tap X FIL to change to next filter tap MODE to change modes and hold to switch from CW normal to CW reverse Whenever you switch modes or filters the K2 will first record your new settings if they have been changed B AND switches
64. it with the 4 915 MHz signal from the RF board to produce a new auxiliary of about 150 kHz This auxiliary signal 1s then amplified by U2B and detected by D1 to create a positive going AGC voltage which 15 then routed back to the RF board to control amp 012 While it is possible to generate the same AGC voltage by simply amplifying and detecting the 4 915 MHz signal itself this technique often necessitates shielding of the AGC RF amplifier stages to prevent radiation of or BFO signals back into the receiver I F strip We obtain all of the gain at 150 kHz instead so the 4 915 MHz signal 15 not re radiated 150 kHz 15 high enough to obtain fast AGC response two orders of magnitude faster than 15 possible when audio derived AGC 1s employed RF Board The RF board is the largest of the three K2 boards and serves as a structural element that the chassis and the other boards attach to This board contains all of the RF circuits amplifiers oscillators filters etc Refer to the RF board schematic Appendix B Sheet 1 Synthesizer The K2 uses a PLL phase locked loop synthesizer IC U4 in conjunction with a wide range band switched VCO Q18 The synthesizer provides approximately 7 dBm output from 6 to 24 MHz which 1 then injected at the transmit and receive mixers sheet 2 Phase noise performance of the synthesizer 1s very good despite its low parts count and absence of shielding Th
65. lengths of enamel wire one red and one green Then twist the wires together over their entire length The wires should cross each other once every 1 2 or 1 ELECRAFT L Wind the twisted wires onto a 1 2 12 7 mm dia ferrite core FT50 43 using exactly 5 turns and covering about 85 of the core Figure 6 27 shows how the winding should look The leads of T3 are labeled with letters A through D on the PC board to avoid confusing them with the numbered leads of T2 and 4 Separate T3 s leads as shown in Figure 6 27 Strip and tin leads being careful not to let the red green wire pairs short together Install vertically as shown by its component outline must be seated flat against the PC board with its leads pulled tight on the bottom side 7S Figure 6 27 ELECRAFT Locate the binocular 2 hole ferrite core for 4 Wind 2 turns of green insulated hookup wire 5 13 cm through the core as shown in Figure 6 28 This forms 1 2 winding Do not use enamel coated wire Cut and strip the two leads using the lengths shown Be careful not to nick the wire 2 1 2 l 7 8 22mm Figure 6 28 Wind 3 turn winding 3 4 on top of the 1 2 winding but with the wire starting and ending on the opposite side Figure 6 29 Use 7 18 cm of white insulated hookup wire not enamel coated wire Prepare the leads in the same manner as above
66. line low during the user programmed QSK delay Selects auto detect mode ADET On default or ADET Off Shortcut If the menu entry you want to change is the last one used you don t need to tap MENU just hold Change the parameter as usual then exit by holding once more ELECRAFT Primary Menu Functions All primary menu functions are listed below secondary menu functions are listed on page 103 Supplemental parameters accessed with DISPLAY are marked see explanation at left STL ST P T R RPT INP IAB SSBA SSBC LCD GRPH OPT ATU RANT CAL PF1 PF2 sidetone level volume 0 255 Tone Source sidetone pitch 0 40 to 0 80 kHz in 10 Hz steps QSK delay 0 00 to 2 55 sec SR Mode CW message repeat interval 0 to 255 seconds CW input selection Auto detect on off PDLn internal keyer norm w auto detect PDLr internal keyer reversed w auto detect HAND hand key or external keying device iambic mode or B SSB audio level mic gain 1 2 3 or BAL SSB speech compression level 1 1 through 4 1 in RTTY data mode a separate compression level is provided and the menu entry is SSBCr DAY backlight off bargraph bright or NITE backlight on bargraph normal LED bargraph selection OFF DOT BAR OPT BATT overrides GRPH BAR forcing DOT mode receiver optimization PERFormance or BATTery see page 100 ATU operating mode RX antenna OFF or ON per
67. male For Speaker Locking Ramp E620024 1 3 Q5 Q21 Q22 2N5109 Pre Amp Post Amp Pre Driver E580013 Q7 Q8 2SC1969 Push Pull Finals E580008 2 Page 6 RF Appendix PICTURE K2 RF Board Parts List p n E850001A and E850001B Designators Q10 Q12 Q17 Q20 Q23 Q18 Q19 Q24 213 016 025 Value Description 2N7000 TO 92 E580002 J310 TO 92 E580012 PN2222A TO 92 0 92 580001 R115 0 05 ohm 1 3W Current Sense BLACK E500050 R116 R68 R67 R50 R42 R53 R54 R83 R76 R82 R84 R43 R78 R112 R15 R55 R56 R92 R97 R45 R47 R74 R7 R35 R36 R94 R113 R6 R8 R60 R64 R89 R30 R48 R49 R61 R85 R58 R1 R2 R63 R77 R20 R46 R98 R99 R10 RAO R72 R88 R90 R11 R12 R41 6 _ 7 5 1 8W grn brn grn for L33 see text BLUE 1 1 4 watt BLUE 1 1 4 watt TAN 5 1 2 watt TAN 5 1 4 watt TAN 5 1 4 watt TAN 5 1 4 watt TAN 5 1 4 watt TAN 5 1 4 watt TAN 5 1 4 watt Part Number QTY 5 Appendix K2 RF Board Parts List p n E850001A and E850001B PICTURE Designators Value Description Part Number QTY R75 R80 680 TAN 5 1 4 watt E500040T 2 R91 R93 R100 820 3 R38 R39 2 R79 R81 2 R62 REG R73 ROS T x TAN 570 14 Wati E500005T 11 x 5114 5 R59 TAN 5 1 4 watt E500047T 1 8110 RIT 2 R33 15K TAN 5 1 4 watt E500060T 1 R26
68. may wish to use the one of the alternative VFO calibration techniques described in the Operation section page 101 You can use an on air signal such as WWV at 10 MHZ to obtain better than 50 Hz VFO dial calibration on all bands ELECRAFT 81 8 Operation BAND AND MODE NUMERIC MEMORY BARGRAPH ANNUNCIATORS INDICATOR KEYPAD 1 9 SELECTION we mes ag SRS aee um e B 5 9 20 40 1 3 RCL VOX REV SPLIT BAND 1 2 RF 3 5 7 10 PRE ATT AGC XFIL ALC 4 ANT2 PRE ATT RT XT STORE TUNE SPOT KEYER POWER CWRV AFIL E r MSG LEVEL PF1 PF2 REC MICROPHONE HEADPHONE VFO NUMERIC RIT XIT POWER JACK JACK KEYPAD 0 OFFSET ON OFF K2 FRONT PANEL 82 INTERNAL BATTERY DISABLE SWITCH RS 232 AND AUX I O INT BATTERY TI on AUX I O 9 15 POWER SUPLY MAIN ANTENNA DO NOT USE IF ANTENNA JACKS FOR USE WITH ATU ANT 1 UNBAL 2 ANTENNA TUNER e e OUT XVTR SEPARATE RECEIVE PHONO RCA ANTENNA CONNECTORS FOR TRANSVERTER ATU IS INSTALLED K2 REAR PAN EL ELECRAFT BNC CONNECTORS FOR TRANSVERTER EXT SPKR e IN XVTR ELECRAFT KEYER PADDLE EXT KEYER OR HANDKEY ELECRAFT This section of the manual explains how to set up and operate the K2 Refer to the illustrations on the previous pages for control locations
69. means the corner closest to you on the left 34 Take moment to familiarize yourself with RF board using Figure 6 1 to identify the major sections If you flip the board over you ll see that there are a few components on the bottom of the board primarily in the transmitter section Band Pass XMTR Low pass Filters Filters Synthesizer Figure 6 1 Assembly Part I Locate a 2 D fastener and hold it vertically as shown in Figure 6 2 Looking at a side with two holes note that the holes are offset from the center When you install the fasteners in the following step be sure to position them so that the holes in the fastener are shifted the same direction as the holes in the PC board outlines on the bottom of the board ELECRAFT Install 2 D fasteners at 5 locations the bottom of board as shown in Figure 6 3 Secure each fastener from the top side of the board using two chassis screws black 3 16 4 7 mm and two 4 lock washers The washers go on the top side of the board Holes offset from center Figure 6 2 Bottom of board i 2 D Fasteners Standoffs 1 4 Figure 6 3 ELECRAFT Make sure that the 2 D fasteners on the edges line up with the edge of the PC board and do not hang over If they hang over or do not match their component outlines they are installed backwards Install two 3 16 4 8 mm diameter 1 4 6 4 mm long round
70. on transmit is normal you probably have a weak battery or inadequate power supply 025 Batteries must be charged using the right voltage or their usable life will be greatly reduced if you have the K2 internal battery option refer to the charging instructions in the option manual Battery life can be extended by reducing power output and by turning off selected features using the menu see Operation Always disable the K2 s internal battery using the rear panel battery on off switch if you plan to use an external battery or a reduced voltage power supply that 15 inadequate for charging purposes Make sure your 4 000 MHz oscillator control board X2 is calibrated Two methods are provided in the Operation section Advanced Operating Features 030 VFO frequency jumps or drifts or operating frequency appears to be entirely incorrect Make sure the bottom cover is installed when doing CAL FIL and CAL PLL Also if you calibrate at room temperature but operate the radio at much lower or higher temperatures calibration will be worse Re do CAL FIL after calibrating the 4 000 MHz oscillator Re do CAL PLL after calibrating the 4 000 MHz oscillator Use CAL FCTR with probe and tune very slowly through about 10 kHz of VFO range if you see any sudden jumps of gt 50 Hz over this range even after doing CAL PLL your 12 096 MHz oscillator crystal may be defective RF X1 You must align both the VCO and BFO using the
71. probe or the PLL Reference Oscillator Use one of the following methods to adjust C22 on the Control board listed In order of preference Connect a calibrated external frequency counter probe to without removing the K2 s internal counter probe Adjust C22 until the K2 s reading matches the external counter s reading Alternatively you can use a calibrated short wave or ham band receiver Set the receiver for LSB or USB mode Connect a short length of wire to the receiver s antenna jack and lay the end near the 4 MHz crystal on the K2 Control board Find the oscillator signal on the receiver Tune the receiver to 4 000 MHz and adjust C22 until you hear a zero beat pitch 0 Hz If you don t have a counter or receiver leave C22 set at its mid point for now You can improve the calibration later using a calibrated signal generator or an on air signal such as WWV at 10 000 MHZ ELECRAFT PLL Reference Oscillator Range Test Set up the K2 internal counter as described for 4 MHz Oscillator Calibration at left first three steps If you have an external frequency counter probe connected to TP3 along with the K2 s internal counter probe disconnect it When you re in frequency counter mode the and switches can be used to check the range of the PLL reference oscillator First tap and write down the frequency reading below typica
72. put the chassis together some results will not be accurate Install the side panels and secure with two chassis screws each Plug in the front panel assembly Secure with two chassis screws Plug in the Control board Secure the front panel and Control boards together using two chassis screws AN Before installing the bottom cove in the next step verify that all components on the bottom of the RF board have an installed height of 1 4 6 mm or less Capacitors or other parts that stand above this height must be bent downward at an angle to prevent them from hitting the bottom cover Install the bottom cover and secure it temporarily using six chassis screws 60 Alignment and Test Part II In this section you ll test and align the PLL phase locked loop synthesizer and receiver circuits Once this 15 completed you ll be able to test the receiver using all modes on 40 meters Connect your power supply or battery and turn on the K2 4 MHz Oscillator Calibration Plug the frequency counter probe into P6 Control board Connect the probe tip to the PLL reference oscillator test point TP3 left front corner of the RF board near U4 Using the menu select CAL FCTR then hold second time to enable the frequency counter The counter should show a frequency of 12090 kHz 30 kHz If it 1s 0000 00 changing rapidly or out of range you could have a problem with the counter
73. quite broad Q25 turns on only if the optional SSB adapter is installed and its fixed bandwidth filter is selected This pulls capacitor C179 to ground which interacts with L34 to shift the second crystal filter s center frequency so that it matches that of the filter The product detector is a Gilbert cell mixer oscillator U11 Due to the loss in the second crystal filter the input voltage to U11 never exceeds the range that the device can handle also provides the BFO signal which is tunable over about a 4 to 5 kHz range by varactor diodes D37 and D38 X3 and X4 have carefully controlled characteristics and are well matched As in the PLL VCXO Q19 sheet 1 the two crystals de Q each other to increase the tuning range of the BFO On transmit the BFO buffer attenuator Q24 is turned on Q24 s drain voltage is controlled by the microcontroller providing BFO amplitude control Precision PIN diode D36 provides additional reduction in low level signal leakage when Q24 1s turned off U10 mixes the VCO with the BFO on transmit and video amplifier U9 increases the signal level while providing a low impedance output to drive the bandpass filters sheet 3 112 Sheet 3 Filters and I O Controller The band pass and low pass filters are switched with latching relays to minimize loss and current drain Only five band pass filters and seven DPDT relays are required to cover nine bands 160 10 m This is accomplished by
74. right top to bottom on the schematic U10A and associated circuitry are used to accurately control power output as well as provide CW waveform shaping The keying waveform 15 sigmoidal S shaped on both rising and falling edges in order to provide totally click free keying Q9 and Q10 form a two stage amplifier supplying a square wave signal to the MCU when the frequency counter is enabled and a probe is connected to P6 The counter amp is turned off at all times except when one of the calibration routines is being used The four outputs from the quad DAC US provide audio tones via U10B BFO frequency control U10D and crystal filter bandwidth control U10C Audio tone pitch amplitude and wave shape are controlled in firmware to yield clean sidetone from 400 800 Hz as well as general purpose tones The bandwidth control line doubles as the transmitter driver bias control on transmit Note The sidetone signal 1s actually generated at pin 4 of U8 which is a logic output while sidetone volume is set by a D to A output of the DAC using 05 as a variable drain voltage saturated switch The DAC cannot be used to generate sidetone directly because the 60 dB channel to channel isolation 1s not adequate to prevent slight modulation of the VBFO and BVIAS lines on transmit 110 U7 provides 2 kbytes of non volatile configuration data storage This memory is used for VCO lookup tables CW messages frequency memories and other variable
75. section b Figure 5 17 1 4 6 4 mm standoff on the PC board should now be visible through the hole just to the left of the encoder mounting hole Secure the panel to this standoff using the 4 40 x 3 16 4 8 mm flat head screw as shown in Figure 5 17b Remove hardware from shaft of encoder Z1 and discard the lock washer which will not be used Insert the encoder through the hole in the Front Panel board Figure 5 18a Cut 1 8 3 mm off the end of each of the encoder s four connector pins 32 Attach encoder to the inside of front panel using nut and flat washer only Figure 5 18 shows the side view a and front view b with encoder properly installed The encoder has a small metal tab near the shaft that will only allow it to be installed one way Do not over tighten the nut Note the green encoder bushing is metal not plastic b Figure 5 18 Attach the four encoder wires you installed earlier to the matching pins on the back of the encoder Each wire should be wrapped securely around the base of its matching pin with no slack in the wire Trim and solder the wires making sure they aren t shorting to each other or to the encoder body which is conductive Set all potentiometers to midway in their rotation AN In the next step a small knob may fit too tightly onto its potentiometer shaft If so rotate the shaft until it bumps u
76. setup Parameter DISPLAY Switch Usage in Mode The DISPLAY switch is used to access supplemental parameters when editing certain menu entries marked above You will normally not need to change these settings Entries which use DISPLAY include Menu Entry DISPLAY Usage PORT Sends an RS232 test message if PORT is ON PA Selects PA fan mode see KPA100 manual TRN1 6 Selects transverter parameters see page 105 D19 Selects PA low pass filter to use on 60 meters PA60 80 80 m filter or PA60 40 40 30 m filter See instructions in K60XV manual 103 Squelch SLCH Squelch defaults to OFF You can set the threshold to 1 10 corresponding to the S meter s bargraph segments Transmitting holds squelch open for about 10 seconds Tuning Rate Selection RATES The RATES menu entry lets you specify how the RATE switch works The four options are 3N 3 rates normal order 10 50 1000 Hz steps 3R 3 rates reverse order 1000 50 10 Hz steps 3C 3 rates CW optimized 10 20 1000 Hz steps 2 2 rates 10 50 Hz steps only Keying Weight DOT DOT sets the internal keyer s dot space ratio keying weight The range is 0 90 1 40 roughly 90 to 140 of normal weighting The default is 1 10 Fast Play CW Messages FPLY CW messages are normally played by tapping MSGI then 0 8 During contests some operators prefer to have one touch access which we refer to as
77. should be removed as follows Using a blunt instrument such as a ball point pen push on the tape through a hole until the tape begins to lift away from the surface Peel tape completely off using a sharp tool if necessary Be careful not to nick or scratch the outer surface of the panel After removing any masking tape place the front panel chassis piece face down with the large round microphone jack hole on the right 29 Locate the green plastic bargraph filter and two pieces of double backed tape These items will be found in a small bag with the serial number label AN Caution The adhesive on the double backed tape is very strong Once you position the tape on the green filter you will not be able to remove it Be very careful to align the tape with the ong edges of the filter as explained below Remove the white paper backing from one side of each piece of tape Attach the tape to the ong edges of the green filter Figure 5 13 Be careful not to get any adhesive on the center portion of the filter since it might be visible after installation align edge of tape with filter Figure 5 13 ELECRAFT 30 Remove brown paper backing from other side of each Turn front panel face up piece of tape then turn the filter tape assembly adhesive side down u Carefully center the green plastic filter over the inside of the LJ Position the clear plastic LCD bezel over
78. the LCD and bargraph LED hole Figure 5 14 bargraph holes as shown in Figure 5 15 The bezel goes on the outside of the panel Secure bezel with four 2 56 screws stainless steel as shown in Figure 5 15 Tighten the 2 56 screws only the amount needed to hold the bezel to the front panel Over tightening may crack the bezel or strip the threaded holes in the panel Green Film Gl D ELECRAFT K2 TR SCEI VER Q 2 56 Screw 4 LCD Bezel Figure 5 14 Figure 5 15 ELECRAFT Remove the insulation from four 1 5 38 mm lengths of green hookup wire Install bare wires on the bottom of the front panel board using the four pads below the large rectangular hole Figure 5 16 Solder and trim the wires on the top side of the board The wires will be connected to the optical encoder Z1 in a later step Figure 5 16 Remove the protective plastic film from the face of the LCD Be careful not to scratch the glass Caution Do not peel off the LCD glass just the thin protective film The LCD will not be usable if you lift the glass itself 3l Insert the front panel PC board assembly into the front panel The pushbutton switch caps on both sides of the LCD should protrude slightly as shown in the side view Figure 5 17a Note the board panel assembly will not be rigidly held in place until it is mated with the RF and Control boards in a later
79. the long handled Allen wrench as described in Part I LJ Remove the bottom cover Remove screws from front panel assembly and unplug it from the RF board Remove the side panels by taking out the two screws along the bottom edge of each panel ELECRAFT Install the following 1 4 watt resistors starting with R46 which is just to the left of I O controller U1 R46 270 RED VIO BRN R45 47 YEL VIO BLK 59 4 7 k YEL VIO RED R61 120 BRN RED BRN R49 120 BRN RED BRN R40 470 YEL VIO BRN R41 560 GRN BLU BRN __ R55 33 ORG ORG BLK R53 4 7 ohms YEL VIO GLD R56 33 ORG ORG BLK R54 4 7 ohms YEL VIO GLD R60 100 ohms BRN BLK BRN R62 2 7 k RED VIO RED R67 1 5 1 BRN GRN BLK BRN R68 226 ohms 1 RED RED BLU BLK AN The 150 pF and 3 3 pF capacitors to be installed below may be hard to identify See capacitor information on page 9 Install the capacitors listed below C12 is near back left corner Note C13 and C14 will not be installed they are included with the 160 m RX Antenna option K160RX C12 560 561 1800 182 C26 001 102 7 C16 1800 182 7 15 560 561 C22 3 3 pF 3 3 C20 47 47 7 C19 330 331 7 C30 470 471 C24 47 47 C25 330 331 7 C35 56 56 C37 001 102 C36 470 471 33 22 pF 2 2 C49 001 102 __ C31 56 56 C242 330 331
80. the top Since all holes are plated through you can solder on either side 12 Integrated Circuits and ESD The K2 transceiver uses integrated circuits and transistors that can be damaged by electrostatic discharge ESD Problems caused by ESD can often be difficult to troubleshoot because components may only be degraded at first rather than fail completely To avoid such problems simply touch an unpainted grounded metal surface before handling any components and occasionally as you build We also recommend that you take the following anti static precautions in order of importance Leave ESD sensitive parts in their anti static packaging until you install them Ground yourself using a wrist strap with a series megohm resistor do NOT ground yourself directly as this poses a shock hazard Make sure your soldering iron has a grounded tip Use an anti static mat on your work bench IC Sockets Sockets are used for only the largest ICs You should not use sockets for the other ICs because they tend to be unreliable and can cause problems due to added lead length Since sockets are not used in most cases you must double check the part number and orientation of each IC before soldering Soldering Desoldering and Plated Through Holes CAUTION Solder contains lead and its residue can be toxic Always wash your hands after handling solder The printed circuit boards used in the K2 have circuitry on both sid
81. to use start with mode A which has less critical timing requirements INP selects paddle normal PDL n paddle reverse or hand key ext keyer HAND These settings are stored in EEPROM so you won t lose them when you turn power off Use the KEYER control to select the desired CW speed The display shows the speed in WPM as soon as you start turning the knob You can adjust the keyer speed even while transmitting ELECRAFT Message Memories The K2 provides nine CW message memories of 250 bytes each Playback features include message repeat and 1 level chaining CW messages can only be recorded using a keyer paddle connected directly to the K2 s key jack Set INP to PDL n or PDLr To record a message Hold 99 and when prompted tap a numbered switch 0 8 to select one of the nine message buffers The display will then show REC 250 indicating that 250 bytes of storage are available in this message buffer This number will count down toward 0 as long as you are sending Whenever you stop sending up to two standard length word spaces will be inserted To stop recording tap MSG If you do this before starting to send the original message contents will not be lost To play back a message Tap MSG then select a message buffer 0 8 Message play can be canceled at any time by hitting M SG again or by tapping the keyer paddle To listen to a message without transmitting use TEST mode switch
82. you must align the dotted end of the network with the pin 1 label on the PC board outline Install the resistor networks listed below top side of the board Double check pin 1 orientation and values before soldering __ RP2 120 10 pins 770101121 dotted end should be near RP2 label __ 1 100 10 pins 10A1 104G dotted end near label Install and solder the diodes listed below observing proper orientation as described in the previous section __ D4 1 5817 __ 05 1 5817 __ D6 1 5817 Install and solder the following capacitors C9 1 located on the bottom of the board and must be soldered on the top side 047 473 2 01 103 _ 047 473 __ C9 01 103 on bottom Install PN2222A transistors at 1 and Q2 near the middle of the board and solder These transistors must be mounted so the lead length above the PC board 15 less than 1 8 3 mm to prevent them from hitting the front panel There are two ground jumpers on the Front Panel board one at the far left and the other at the lower right labeled with symbol Use discarded component leads to make 3 4 19 mm long U shaped wires for each jumper Solder them on the bottom side Install a 40 pin IC socket at on the bottom of board The IC will be inserted into this socket later Orient the notched end of the socket to the left as shown on the PC board outline 24 AN The IC
83. 0 15000 Select 80 meters and set the VFO for about 4000 kHz lm 18000 18200 15 21000 21450 Connect a DMM digital multimeter to the left end of resistor 12m 24800 25000 R30 near the center of the synthesizer area of the RF board and 10m 28000 28800 ground Use a small alligator clip to ensure a good connection You can also use the built in voltmeter to measure the VCO control voltage Refer to Voltmeter Probe Assembly in Part I AN It 1 possible to damage the slugs in slug tuned inductors if you use a metal tool or if you tune the slug too far in or out The tuning tool provided will not damage the slugs Using the wide end of the plastic tuning tool adjust the slug in inductor L30 until the voltage at R30 reads 6 0 V If the voltmeter reading does not change at all as you tune L30 through its full range refer to Troubleshooting If the voltage changes but you cannot get to 6 0 V you have probably wound the VCO inductor T5 incorrectly or have installed the wrong value at L30 or C72 Set the VFO for approximately 3500 kHz Measure and write down the VCO control voltage at this frequency in Table 6 1 using pencil For each remaining band set the VFO to low and high frequencies listed in Table 6 1 and write down the VCO control voltages You can tune quickly to the approximate frequencies in the table by selecting the 1 kHz tuning rate Usable VFO cove
84. 0 196 3W ON J AF OUT Current Sense 4 R35 R36 Y 82 Panel Board OFF C105 SB530 2 2uF C106 2 20F R113 S1 ST PS Power Q23 z 2N7000 5 Elecraft K2 RF Board J2 By W Burdick Rev Date Sht E Swartz F 1 27 04 1 of 4 NOTE 1 X2 is not used C111 2 2uF NOTE 2 019 020 are supplied with the K60XV option They must not be installed unless the K60XV option is E also installed 60 m band and transverter I O C71 must be changed to 120 pF if D19 D20 are installed 3 These components improve PLL stability they must be soldered on the back of the board see text D6 1N4007 Sh 3 Attenuator 10dB D7 1N4007 Buffer i i R96 i L LT1252 SPK 7 3 C54 R92 4 01 33 R93 R95 820 2 7K RFC13 Q20 2N7000 T 15 R94 C55 aL 82 N C157 L 01 047 C150 Nn 330 Xmit Mixer R91 C156 820 047 gt R75 680 R72 470 R73 2 7K Noise Blanker m a C161 gt 01 022 2N5109 R89 2N5109 as R83 WE HA 479 R84 NB Bypass R88 R90 RF Preamp is jen jon 14dB 7 7 R77 01 ae Q12 NOTE If Noise Blanker is installed Post Mixer Amp anton R88 and R90 must be removed j and R89 replaced with a jumper 12V 4 9136 MHz Variable Bandwidth Crystal Filter V BIAS XFIL IF Amp R101 V XFIL2 C185 R112 as TS 8R Product Det RP4 RP5 100K 55 NOTE 2 dis 5 1N4148 U12 V XFIL2 UI MC1350 R100 C178
85. 0 7 2 5 VDC Actual If VPWR reading is high gt 4 5 V The ALC software will set VPWR to its highest level about 5 V if the transmitter cannot be driven to the requested power level This happens for one of two reasons a the transmitter gain is low or transmitter isn t working at all b the RF detector has an incorrect component Check all component values in the RF detector If you can t find a problem with the RF detector continue with the next signal tracing section transmit mixer etc If VPWR reading is low 0 4V VPWR can be too low because a the ALC software is being fooled by a signal from the RF detector that says the power 15 higher than it really is b because U8 on the control board is defective or has a pin shorted to ground or not soldered Check all component values in the RF detector RF sheet 3 If these appear correct check DC voltages on 08 control as well as resistance to ground on all pins Transmit Mixer Buffer Band Pass Filter T R Switch RF sheets 2 3 Note The measurements in this section and the next may vary widely especially if you do the measurements on a band other than 40 m However the ratio between any two back to back measurements should remain fairly constant and is a good indication of gain or loss of a stage in the transmitter For example the ratio of measurements in steps 3 and 2 below 15 about 12 l 2 Connect the RF probe to the DMM Set the DMM for
86. 1 8 MHz 160 m and 5 MHz 60 m bands will not appear in the band list unless the associated options are installed This can be done only after assembly and alignment have been completed The supply voltage reading will reflect a small drop across D10 the reverse polarity protection diode typically 0 1 V on receive Current readings may vary at this stage of assembly but should be under 150 mA 43 Tap switch three times You should hear relays switch each time RF Probe Assembly The Switch Spacing Tool used during Front Panel can now be used as the PC board for the RF probe All parts for the probe including a ground alligator clip 2 feet of RG174 coax and banana plugs for a DMM are supplied with the kit You can assemble the probe at any time using the instructions on page 9 of Appendix E Voltmeter Probe Assembly If you do not have a DMM digital multimeter you can use the simple DC voltage probe shown below in conjunction with the built in voltmeter The crimp pin and 2 pin housing can be found in the MISCELLANEOUS components bag Assemble the voltage probe as shown in Figure 6 13 using green insulated hookup wire No ground connection is needed since you will be measuring voltages inside the K2 Hookup wire 12 0 3m Housing Tinned lead RON 0 5 13mm Figure 6 13 L Plug the voltage probe assembly into P5 on the Control board The probe sh
87. 19 120 L25 L26 44 2 1 25uH 0 89uH 7 L5 33pH solenoidal green body orange orange black E690007 1 9 RFC6 0 68 solenoidal reen body blue gray silver E690008 1 RFC1 RFC2 RFC12 RFC13 100pH solenoidal green body brown black brown E690004 A RFC4 RFC5 RFC8 10uH solenoidal green body brown black black E690009 4 100UH solenoidal RFC15 subminiature very small tan body brown black brown E690013 1 15uH solenoidal green body brown green black E690006 1 RFC10 1mH solenoidal green body brown black red E690010 1 0 37 dia ferrite core GRAY 47uH 16T RFC11 100pH 20T RFC11 RFC14 RFC16 RFC14 18uH 10T RFC16 47uH 16T 0 37 dia ferrite core GRAY T1 9 3T T2 12 8 T1 T2 T6 T7 FT37 43 T6 10T bifilar T7 5 20T m m m m O O O O cO O O O O O O O O O O NO cO 8 Toroidal transformer on 0 50 dia ferrite FT50 43 core GRAY 5T bifilar 1 Toroidal transformer on 0 50 dia iron T50 6 powder core YELLOW 1 3uH 16 4T E680010 1 Page 5 RF Appendix PICTURE K2 RF Board Parts List E850001A and E850001B Designators Value Description Part Number QTY T4 Binocular core 2 3 1 1 Balun Core Square Two Holes E69001 1 1 2 GRAY ferrite beads ea on bare wire Z1 Z2 Ferrite Bead see text E980029 4 1 20 x 1 male RA 20 pin male right angle To Front Panel J1 620029 1 5 2 pin
88. 2 12 C23 Rie T 109 50pF 50pF 9 1N4007 8T 01 d gt L ZVN4424A C32 i C34 Pa LPF LD 5 30pF 5 30pFZ C35 T R Sh 4 30p 30p O RFC7 56 26 PRE DRIVER Switch 15uH 10 12m O 3 L10 1 5 1 7m 8 C30 C36 Sh 4 0 2 1uH C214 470 H 470 9 ds K10B 10m 17m fos Low Pass Filters K10A 52 212 C104 150 12m 15m x 7 15 17 Controller 2 I C44 5 30pF C46 5 30pF K7B I 2 C219 C221 9 12 39 C43 C45 1 C47 6v U1 100 C218 L C222 ES 12V IN OUT AUXBUS K11A Hop C220 100 K11B L12 C139 PIC16C72 3 L13 8 e C42 10 12m C48 0 1 16 872 pine aon 398 9 40 60 7 5 9 8 x BPF Relays 41 TU ee i v VCO Relays v 3 8 gt Band Pass Filters Du 2 9 2 K13 1 Ki C228 C229 56 220 K14 K4 C225 C227 K7 C226 680 K6 RF Output Detector R67 ALL RELAY BYPASS CAPACITORS ARE 001uF C39 D9 1 5K C82 R66 001 lt 001 V RFDET C17 C27 C195 C204 C207 C216 C223 27K 1N5711 1 K10 RF R69 77 R68 ee K11 G 001 2260 NOTE1 When the K60XV transverter and 60 option is installed 10 C6 must be removed and J15 installed in its place on K17 K9 the top side of the PC board Elecraft K2 RF Board C208 By W Burdick Rev Date Sht E Swartz F 1 27 04 3of4 Appendix B NOTE2 Pins 5 and 6 of relays are not connected internally However these pins may be connected to other relay pins or to oth
89. 28 8 160 m opt 1 8 2 0 60 opt 5 0 5 5 Stability lt 100 Hz total drift typ from cold start at 25 C 30 Hz over a 500 kHz range typ when calibrated 3 Accuracy Resolution 10 Hz Tuning steps 10 Hz 50 Hz and 1000 Hz nominal other step sizes available via menu 20 10 assigned to 160 10 m Bands 10 general purpose Memories RIT XIT range 0 6 to 4 8 kHz selectable 10 40 Hz steps depending on range Fine RIT mode steps 2 3 Hz typ gt The K2 can receive well outside the indicated bands but this extended range is not specified or guaranteed Transmit ranges may be limited for export to some countries The K2 100 KPA100 option limits transmit from 25 27 999 MHz to 10 watts or less See Frequency Calibration Techniques page Transmitter Power output range Min supply voltage recommended Duty cycle Spurious products Harmonic content Load tolerance T R delay External keying CW sidetone Keyer Keying modes Speed range Message memory 0 5 W to gt 10 W typ power setting resolution 0 1 W accuracy 10 5 W 9 0 V min for 2 watts out 9 5 V min for 5 watts out 10 0 V min for 7 watts out 10 5 V min for 10 watts out 5 W 10096 10 W 50 40 dB or better 10 W 50 typ 45 dB or better 10 W 55 typ 2 1 or better SWR recommended will survive operation into high SWR approx 10 ms 2 5 sec adjustable 70 WPM max 400 800 Hz in 10 Hz steps
90. 392G E510014 1 9 1K 5R ISO olp resistor pack 10 pins ALT 2338 SIP resistor pack 8 pins ALT 77083933 EStOOTG RP7 333G SIP resistor pack 8 pins ALT 77083333 E510016 1 RP3 4 770103473 E510007 82K 4R ISO 736 SA602AN AGC Mixer 5 612 Alt 8 pins E600006 L L L LMC660 M833N Dual Op Amp 8 pins E600012 MC6482AIN Dual Op Amp 8 pins E60001 1 M380N 8 Audio Amplifier 8 pins E600019 a 00000 Quad Op Amp 14 pins E600025 1 MAX534 Quad 8 bit DAC 16 pins E600031 1 U1 U2 U3 U9 07 U10 U8 U4 LM2930T 8 8 Volt regulator TO 220 Pkg E600018 1 U5 25LC320 EEPROM 4K x 8 8 pins E600009 7805 7805 1 7805 5 Volt regulator TO 220 Pkg PIC18C452 MCU Programmed 40 pins O O O O O O N N A Page 3 Control Appendix K2 Control Board Parts List 50002 PICTURE Designators Value Description Part Number QTY Crystal HC49 may be standard or low X1 5 068Mhz profile E660009 X2 4 000MHz Crystal HC49 standard E660006 1 MISC 40 pin socket socket for MCU E620017 1 Bm MISC 2 pin shorting jumper For use with P7 voltage source select E620055 1 PCB1 Control Printed Circuit Board Control 100084 1 4 Control Appendix K2 Front Panel Board Parts List p n 50003 PICTURE Designators Value Description Part Number QTY C1 C3 047 Monolithic 473 E530025 2 2 9 Mon
91. 6 or 560 4 C88 C153 C104 C214 ua s0007 4 C71 C174 C210 NPO 82 or 820 3 C5 C7 C144 C154 C179 C197 C222 100 NPO 101 E530016 7 C84 C85 C202 NPO 151 markings on rear side may C200 C212 C218 150 include 041 RKF E530049 3 C173 C199 C201 C220 229 220 NPO 221 E530042 5 C72 C19 C25 42 C48 150 227 530043 6 C169 C228 2 C30 C36 530004 2 C12 15 2 C127 C128 C226 530053 3 C4 C8 2 C190 C192 E530005 2 C11 C16 C197 1800 3 C96 Monolithic Cap Thick 105 E530037 1 C105 C106 C111 3 093 530045 125 C126 530063 C60 C137 2 C103 Page 2 RF Appendix PICTURE K2 RF Board Parts List p n E850001A and E850001B Designators Value Description Part Number QTY ceramic trimmer see below to tell from 50 C44 C46 C32 C34 var 5 30pF pF E540001 ceramic trimmer red mark or bagged C21 C23 var 8 50pF separately E540000 1N5711 orange glass body E560004 D1 D2 D3 D4 D5 D6 D7 1N4007 large black body silver band E560001 D8 D11 D13 D18 D40 D41 1N4148 clear or blue glass body E560002 5082 3081 FRAGILE clear glass body E560014 ultra low drop shottky diode 9A very large 010 9550015 black body E560009 58530 alternate D12 1N5821 shottky diode 5A very large black body E560003 D16 D23 D24 D25 D26 D39 TO 92 2 leads also D19 D20 see description MV209 019 020 supplied with KGOXV option E560006 D17 D21 D22 D29 D30 D31 D32 D33 D34 D3
92. 6 or the I O controller RF U1 Reduce power You may have power set higher than the final amplifier can achieve resulting in overdrive of all transmitter stages Try reducing power to see if normal current drain is observed at lower power levels Damaged PA transistors or other components could cause inefficiency in any stage of the transmitter Check all DC voltages and components signal trace if necessarily 155 If the keyer is stuck at a fixed speed or the sidetone pitch won t change go into the menu and see what sidetone pitch your have If it s not in the range of 0 40 0 80 kHz you may have bad data in the EEPROM See Resetting the Configuration to Defaults in the Advanced Operating Features section If the keyer is generally erratic when transmitting and seems to get worse as power is increased you probably have RF leaking into the keyline Try bypassing your key with 001 uF capacitors also try 100 uH chokes in series with the paddle and ground connections If your antenna 15 connected directly to the rig with no coax 1 e internal ATU the only way to cure RF problems with the keyer and other circuits may be to reduce transmit power seek a better antenna match or improve your ground system Operation and Alignment 200 249 Problem 201 EEPROM initialized 230 BFO not connected to frequency counter 231 VCO not connected to frequency counter 232 CAL PLL on wrong band 235 PLL ref osc
93. 7 D38 15 149 92 2 leads E560005 Resettable fuse YELLOW G300 Looks F1 RGE300 like a larger monolithic cap E980018 J8 10x2 female socket 10 x 2 female socket E620038 J7 18x2 female socket 18 x 2 female socket E620039 2 1mm jack 2 1 mm DC barrel connector E620026 Page 3 Oo N gt 11 RF Appendix 2 RF Board Parts List p n E850001A and E850001B PICTURE Designators Value Description Part Number QTY 6p female socket 6 x 1 female socket E620037 1 Antenna connector E620020 1 Keyer Jack Threaded Stereo Vertical orientation E620027 1 Stereotiso sw Headphone jack Horizontal Orientation E620028 1 Variable Ind TOKO 15 17m BPF 10 12m BPF Small L10 L11 L12 L13 710504 adjustment slot E690002 4 Variable Ind 4 7 uH TOKO VCO IF 40m BPF 80 160m BPF L30 L1 L2 L3 L4 L8 L9 L34 T1005Z 20 30m BPF Large adjustment slot E690001 8 Page 4 RF Appendix 2 RF Board Parts List p n E850001A and E850001B PICTURE Designators Value Description Part Number 12uH Shielded solenoidal shielded BLACK Pre wound toroidal FRAGILE LEADS HANDLE WITH CARE inductor 41 uH 5 SEE TEXT FOR MOUNTING T44 7 core INSTRUCTIONS USING 1 8W RESISTOR E690018 1 Toroid BLACK 12 10m LPF 32uH L21 L22 L23 L24 T44 10 26UH 17 15mL PF 45pH E680009 4 Toroid RED 80m LPF 2 50uH 20 30m LPF 58yuH 44pH 71 40M LPF L16 L17 L18 1
94. 7 C43 33 33 7 C48 330 331 C47 33 33 C45 1 pF 1 C115 01 103 C117 047 473 C116 33 33 C121 0 01 103 C131 0 1 104 01 103 C120 01 103 C124 0 1 104 C129 01 103 C190 1200 122 7 C210 82 82 C130 0 1 104 C127 680 681 7 C197 100 101 C211 10 10 __ CI28 680 681 7 CI91 1800 182 7 CI98 27 27 7 C218 150 151 65 42210721212 7 C221 39 39 7 213 33 33 7 C199 220 221 7 C201 220 221 C138 047 473 7 C220 220 221 212 150 151 C200 150 151 7 C192 1200 122 __ C222 100 101 C214 68 68 7 C208 47 47 C202 120 121 AN There are two types of ceramic trimmer capacitors used in the band pass filters 30 pF and 50 pF These may look identical They will either be bagged separately or the 50 pF trimmers will have a red marking Install the trimmers listed below starting with C21 near the back left corner Orient the flat side of each trimmer capacitor with the flat side of its component outline This orientation is required to prevent RF pickup during alignment C21 50 pF C23 50 pF __ C32 30 pF __ C34 30 pF C 30 pF C46 30 pF Set all of the trimmer capacitors just installed to their mid way points see Figure 6 23 Use a small flat blade screwdriver Figure 6 23 Install L5 a 33 uH RF choke ORG ORG BLK
95. 8 60 15 50 Po 7 5S5 11 19 00 5o 60 U 1 Jo JUI faa Q6 NI bL 2 so dq 2 pia 05 dp L E 116 2 Joo jso 3 Joo 11 oe B 23 23 Joo 4 jso 14 jso j c 132 14 foo 5 L ip o2 13 foo 6 o 6 L E Joo B 20 oo 7 j0t4 7 56 ma si Cc 125 27 oo 0 Oo J C 06 8 NS NENNEN O23 S 100 28 55 c 2 004 3 o u 137 0o4 2 79 _ Q0 S 116 D 80 JGNDJOO 3 04 13 0 16 181 oo 4 F o 34 2 US 1 2 5 5 39 22 6 6 25 L B 0 3 Ja J 7 Jows 17 oo 11 410 me j E Parts Placement Drawing Appendix F 13939373 2002 SH I OL 9181 9 SIS 6 595 N 1 220 N 74HC165 AdIS H3H LO NO qa 13 38 LI T R 021 edd 2 14VYO31A 2002 9 TOULNOO 2 Mc8 047 lt gt 3 8 8 6 s j CG Os 250 0 A ped 11 C C 0
96. B adapter kit you should install them now Follow the third and fourth assembly steps under Front Panel Board Components in the KSB2 manual page 16 Visual Inspection Make sure there are no components installed backwards Check all diodes resistor networks electrolytic capacitors and ICs The parts placement drawings in Appendix F will be helpful in verifying the orientation of diodes Examine the bottom of the PC board for solder bridges cold solder joints or unsoldered components ELECRAFT Resistance Checks Set all potentiometers to their mid points approx Perform the resistance checks to ground listed below U1 is on the back of the board Ul pin 6 11 TES 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ELECRAFT Front Panel Final Assembly Locate the front panel chassis piece Place it on a soft cloth to protect the finish and labeling AN In the following step the paint masking material will be removed from the inside of the front panel The masking material is usually green but may appear gray because of paint overspray DO NOT remove the masking material from the other chassis pieces at this time Some holes in the front panel were masked on the inside surface during painting If masking tape usually green in color 1 still present you ll need to remove it The holes that are masked are in the four corners along the top and bottom edges Masking tape
97. D 15 33 ORG ORG BLK R14 10 BRN BLK ORG 13 10 BRN BLK ORG R12 560 GRN BLU BRN R17 100 k BRN BLK YEL __ R11 560 GRN BLU BRN 5 2 7 RED VIO RED R78 22 RED RED BLK 100 BRN BLK BRN 68 BLU GRY BLK R8 100 BRN BLK BRN _ 92 33 ORG ORG BLK R91 820 GRY RED BRN R93 820 GRY RED BRN 72 470 YEL VIO BRN R95 2 7 RED VIO RED 896 2 7 RED VIO RED R74 47 YEL VIO BLK 73 2 7 RED VIO RED R97 33 ORG ORG BLK R80 680 BLU GRY BRN R81 1 8 k BRN GRY RED R79 1 8 BRN GRY RED R82 18 BRN GRY BLK ___ R101 10 BRN BLK ORG 107 100 BRN BLK YEL R111 5 6 GRN BLU RED 22 RED RED BLK R90 470 YEL VIO BRN R89 100 BRN BLK BRN R88 470 YEL VIO BRN R84 18 BRN GRY BLK R85 150 BRN GRN BRN R83 4 7 ohms YEL VIO GLD L Install the resistor networks Start with RP2 which is in the front left hand corner Align the pin 1 mark on each resistor network with the pin 1 end of its component outline RP2 10 k 8 pins 8A3 103G RP6 100 k 8 pins 8A3 104G __ 100 k 6 pins 6A3 104G __ 5 100 k 6 pins 6A3 104G NOTE RP3 is not used The Thermistor PC board will be installed at this location as described on the next page ELECRAFT LJ Locate the PLL Upgrade kit which should include the Thermistor PC board and all other parts listed below
98. DSP2 Note If you have the KSB2 installed you can use CAL FIL to configure FL1 as OPI SSB option filter CW and CW reverse modes and leave FL2 4 at the narrower factory defaults 0 7 0 4 and 0 2 Details on how to do this setup can be found in the SSB adapter manual CW Frequency Display In CW mode the frequency shown on the LCD takes into account an offset equal to your sidetone pitch This allows you to determine a station s actual carrier frequency by matching their pitch to your sidetone rather than by zero beating the signal The ED switch can be used for this purpose Operate vs Test mode If you want to try out the keying without actually transmitting hold the VIT switch until the display shows T EST The mode letter C on the LCD will flash to remind you that you have disabled transmit Holding the switch in again returns to OPERate Sidetone Setup Key the rig in TEST mode and listen to the sidetone volume and pitch To change the volume use the menu s ST L entry sidetone level The pitch can be changed using the ST P entry sidetone pitch ST 1 used often so you might want to assign it to ml or see Advanced Operating Features Break in QSK delay The QSK delay is set using the T R menu option setting of 0 00 15 fastest although you may prefer the break in sound with 0 01 selected especially when using headphones 0 05 is about right for casual operation You can select a longer delay up to
99. FO frequencies and VFO tuning rate Current VFO A or B Operating mode CW USB LSB and CW Normal reverse AGC slow fast Preamp and attenuator on off Noise blanker on off requires noise blanker option ANTI 2 selection ATU option Receive antenna on off 160 m RX ant option 9 The receiver is not intended to be general coverage narrow band pass filters are used at the front end to reject out of band signals If you attempt to tune too far outside an available band receiver sensitivity and transmit power will greatly decrease and at some point the synthesizer will lose lock 92 Default Frequency Memories When you first turn on the K2 each band memory 1 preset as follows VFO A is set to first multiple of 100 kHz above the band edge e g 7100 24900 VFO is set to the U S CW frequency for that band Other defaults include CW mode VFO A fast AGC preamp ON above 40 meters and OFF on 40 m and below noise blanker OFF and high threshold antenna 2 OFF antenna 1 selected receive antenna OFF normal receive operation Memories 1 8 are preset to the same values as the 160 10 meter band memories respectively Store and Recall Ten memories are provided numbered 0 through 9 Each memory stores the same information that is stored per band To store the current setup in a frequency memory hold until you see ENT 0 9 then tap one of the numeric keypad switches To recall a stored setup hold u
100. Fast Play To use Fast Play First program 21 or FPon for use in turning Fast Play mode on off Next use the FPLY menu entry to select a switch group For example if you have FPLY 2 5 selected you can use 2 3 4 and 5 for Fast Play The functions of these switches won t be available in CW mode functions are unaffected When Fast Play is on the letter F will replace the mode letter C once every few seconds as a reminder A tap of any Fast Play switch will play its message buffer one time To auto repeat you must still use MSG as described on page 97 104 RS232 Interface Setup PORT Use the PORT menu entry to turn on 4800 baud RS232 communication When PORT is ON tapping DISPLAY sends FA command VFO A frequency for test purposes Refer to the KIO2 or KPA100 manual for details SPLIT RIT XIT Configuration SPLT Normally the K2 s JASBI RIT and XIT selections stay the same as you switch from one band to the next To have these selections stored on a per band basis and retained when power 15 off set SPLT to PER per band 10 and 12 m Power Limit in SSB RTTY Modes Po26 The highest distortion free single sideband power output level may be less than 15 watts especially on 10 and 12 m We recommend leaving Po28 at 10 0 watts Does not apply to CW mode RTTY Data Mode RTTY RTTY Data mode mode letter lower case if enabled provides fou
101. I If you peaked L8 and L9 when signal tracing through the 30 m band pass filter you ll need to re peak C21 and C23 on 20 m 3 Leave the frequency counter cable connected to TP2 BFO 4 Connect the speaker and re install the top cover Transmitter The following procedure can be used to isolate problems with the transmitter the transmitter area of the RF board 1s identified in Figure 3 CW mode is used for these tests If you re having difficulty with the SSB adapter make sure the transmitter works on CW first then proceed with the signal tracing instructions the SSB adapter manual Once you find a location where the signal appears to be much lower than expected stop signal tracing and check that circuit Check all component values and DC voltages see DC Voltage Tables Closely examine the PC board for unsoldered pins and solder bridges One of most likely causes of a transmitter problem is a poorly soldered toroid lead Re heat any suspect leads or solder joints Preparation for Transmitter Signal Tracing 1 Make sure basic display and control circuits are functioning before attempting transmitter testing 2 Remove the SSB adapter 1f installed and install temporary jumpers at J9 and Temporarily re install C167 001 uF or higher between pins 7 and 12 of J11 See RF board sheet 2 3 12V supply check Use your DMM to check the DC voltage at the cathode banded end of D10 right edge of the board Expected 9
102. IG UP FUNC 5V GND GND 1 SQV31 AV 134 QN38 LON OG
103. If power output is too low go to 155 If power output slowly increases during key down go to 160 If current drain on transmit is too high for the 160 Power output given power level or you see HI CUR go to fluctuates 175 If the transmitter output power seems to be unstable go to 160 If the transmitter stops transmitting by itself go to 170 If the keyer isn t working properly go to 180 Use the signal tracing procedure You may have CAL CUR current limit set too low 2 00 A recommended at 10 W Check power output when using a 500 dummy load if the output 1 correct on a dummy load but not when using an antenna your antenna is probably not matched Install the bottom cover all six screws to prevent RF pick up by low level circuits Check all component values in the RF detector you may have two resistors swapped R67 R68 R66 R69 or the wrong detector diode D9 should be 1N5711 Y ou may have a short in the LPF or BPF reset all of the relays before trying to look for shorts 065 Examine transformers 1 4 carefully these must be wound as indicated in part III of the RF board assembly section see this section for drawings Check all DC voltages in the transmitter RF board Q5 Q6 Q7 Q8 as well as the ALC circuitry control board U10A and RF board Q24 One component that should be checked specifically 15 R50 driver which can open if the driver current goes too high Make an RF probe and signal trace through the tran
104. L FIL menu function provides the means to control how wide the filters are and where the BFOs are located in relation to them The numeric parameters you select using CAL FIL are translated into voltages that control the filter and BFO by means of voltage variable capacitance diodes or varactors Microcontroller The K2 s microcontroller is an integral part of all transceiver operations Firmware 1s used to advantage to provide many functions traditionally provided by discrete control logic For example the VCXO PLL reference oscillator 15 linearized on each band by a firmware auto calibration routine with resulting tables stored in EEPROM Another example is firmware ALC which is used on CW to maintain the user specified power level across all bands The SSB adapter when installed provides its own optimized hardware ALC Extensive use of firmware also results in many useful operating features not usually found on transceivers in this price class These features include built in test equipment frequency counter and digital voltmeter auto calibration dual VFOs memories split operation RIT XIT and a versatile keyer Provisions have also been made in firmware to support a wide range of option modules See full feature list elsewhere on the web site 108 Latching Relays Latching relays are used for all filter VCO and option switching so there is no relay current drawn during normal operation This combined with
105. LED bargraph DS2 is used to display received and transmitted signal strength and ALC level Using the menu the operator can select OFF DOT or BAR mode for the bargraph with OFF or DOT modes typically used to save current during battery operation U3 and U4 are 8 output MOSFET driver arrays which control the bargraph among other things Q1 and Q2 form a brightness control When the NIGHT low control line is pulled to ground by U3 the bargraph supply voltage drops to 2 7 V resulting in about 6 mA LED The LCD backlight is also turned ON in this case When NIGHT low is left high for daytime use each LED draws about 18 mA and the LCD backlight is OFF A high quality optical shaft encoder Z1 provides 100 counts per turn VFO tuning steps of 10 50 or 1000 Hz per increment are used resulting in 1 5 and 100 kHz per turn respectively The encoder is also used to modify parameters in the menu The encoder can be turned off by U3 to save current under certain operating conditions 51 516 are pushbutton switches Switch data is read by U2 an 8 bit parallel to serial shift register Each switch has at least two functions the top label corresponds to a TAP short press and the bottom label corresponds to a HOLD long press 0 5s Switch combinations are also supported although only two are used BAND and BAND together enter direct frequency entry mode and AGC with PRE ATTN turns AGC on or off DC stands for Inter IC Communication
106. LH Jt 80 i x C js 3 36 ose Q2 E 80 Ur 1 jos 9150 14 oo 2 15 25 1511 15 121 7 __ 3 oo 6 9 jox 16 J67 j S joo 4 69 7 os 40 55 17 137 j L jq G6 100 254591 UT T 55 ce pes po qo qo 3 p D 6 jso 9 0051 2 4 S joo 7 75 10 so 3 50 2 soe G 50 8 80 u jso 4 sort D joo 1211 69 12 oo L5 159 d s S joo 2 69 11 J2 6 E qd Some pL qo y G oors 3 69 1 24 _ 7 50 6 _ 50 j J D 105 4 o0 151 50 17 150 j 55265124 15121 eo Cj p q 2 5551 D j e 7 733 18 00 3 50 10 ose Q G 27 19 50 4 00 c amp 5 US 1 0506 00 2 ose D 5e6 21 190 6 50 m jos j Q8 E 70 3 J137 2 50 7 50 j 1 jos j 147100 23 50 8 ors 3 5 129 qp 11 _ 09 E 6 125 25 00 C p 07 J 7 25 i26 so u jso ___ Lr c mz J 77 00 12 00 LE qp d 100 E 00 U4 IN 37 28 50 50 j j j B 07 GND 00 29 50
107. LSB and return to FL 1 using XFIL E Enc uen You should then see a display similar to 10 Set up each LSB filter bandwidth according to the table This 3 Using the VFO knob set FL 1 to the value shown for CW i Mc T i Normal 1 50 Tap X FIL to save the new value and move to ap and set up each LSB BFO as you did for CW FL2 CW Reverse bandwidth will also be updated Iq MODE secet re M e up 13 If you use settings that differ from the defaults record them in Set up FL2 FL3 and FL4 in the same manner 21514 Table 8 2 Use pencil since you may change them later Table 8 1 Recommended Filter and BFO Settings CW only K2 EH 90 Basic K2 Operation Mode Selection Tap MODE to cycle through the operating modes noting the change in the mode indicator letter C CW L lower sideband U upper sideband If RTTY data mode is enabled r RTTY data will also appear in the mode list see page 104 Sideband Inversion The K2 inverts the sideband on 15 meters and above due to the frequency mixing scheme the upper and lower sidebands of the signal become reversed In CW Normal mode the pitch of CW signals goes up with frequency on the lower bands on 15 m and up the pitch goes down with frequency Receiver Configuration Gain Controls The RF GAIN control should normally be set fully clockwise Adjust the AF GAIN control for comfortable volume Sidetone volume is s
108. RN BLK BRN Install the ceramic resonator Z5 near U1 Z5 looks like a capacitor with 3 pins It can be installed in either orientation Install R65 10 BRN BLK ORG on the bottom of the board near U1 ELECRAFT L Install D8 and D18 1N4148 on the bottom of the board toward the right edge Make sure the banded end of each diode is aligned with the band on its component outline AN In the steps that follow you ll install the connectors that mate with the control and Front Panel boards These connectors must be installed properly to ensure reliable mechanical connection They are very difficult to remove once installed so follow all instructions carefully Review Figure 3 3 page 8 for correct placement Install 6 pin single row female connector J6 which is just left of the power switch It must be seated vertically on the board and must not be tilted Figure 6 4 Solder just one pin near the center of J6 J6 Figure 6 4 If J6 does not appear to be completely flush with board re heat the soldered pin and press down Once it is installed correctly solder the remaining pins L Install the 20 pin dual row female connector J8 near the front left corner of the board Use the same technique you used for J6 This connector must be seated flush with the board before soldering Install 36 pin dual row female connector J7 in the same manner as J6 and J8 ELECRAFT Positio
109. RP6 a 5 1 10 pin resistor network RP means resistor pack another name for resistor networks RP6 15 usually labeled 770103512 Check the parts list for alternative resistor network labels if necessary Pin 1 of RP6 15 indicated by a dot Locate component outline for RP6 at left end of PC board Install the resistor network so that the end with the dot is lined up with the 1 label Make sure the resistor network 15 seated firmly on the board then bend the leads at the far ends opposite directions to hold it in place Do not trim the leads Do not solder RP6 yet AN Components with many leads are difficult to remove once soldered Double check the part numbers and orientation Install remaining resistor networks order listed below Do not solder them until the next step 3 9 10 pins 770103392 RP7 33 8 pins 8A3 333G RP2 82 8 pins 77083823 3 47 10 pins 10A3 473G RPS 470 10 pins 10A3 471G Rh4 82 8 pins 77083823 LJ Solder the resistor networks No need to trim the leads Install potentiometer R1 50 located at left side of board R1 will sit above the board due to the shoulders on its pins Hold it place flat not tilted while soldering J Install the 82 mH shielded inductor L1 as shown by its component outline Make sure the L1 is pressed down onto the PC board as far as it can go then bend t
110. S menu entry lock unlock VFO DP flashes select operating mode CW LSB USB CW oper test SSB PTT SPEECH 0 2 1 0 These functions require option modules see page 113 y RE ATT 5 79 BH E m TI 2 slo Two Switch Combinations gt lt gt MS do bj T II mio lt lt 85 turn on preamp or attenuator CW audio spot signal on off turn on RIT see RIT menu entry page 104 activate programmable function 1 select A or B VFO temporary A B VFO swap used in SPLIT select FAST SLOW AGC toggle between CW norm reverse or USB LSB turn on XIT see RIT menu entry page 104 activate programmable function 2 set both VFO s to current VFO frequency toggle between SPLIT and NORMAL transceive select next crystal filter FL1 4 audio filter mode OFF AF1 2 CF1 4 SF1 4 play or chain CW msg 08 to repeat use record CW message 0 48 cancels record hold both switches direct frequency entry e g 7 10 40 AGC on off mode letter dec pt flashes XFIL display crystal filter and bandwidth AFIL SPLIT AFIL REC DISPLAY RIT XFIL plus audio filter setting if applicable DSP notch filtering on off DSP noise reduction on
111. SSB adapter you can easily change the settings to take advantage of the optimized fixed bandwidth SSB filter 63 VFO Linearization Make sure the bottom cover is securely attached Allow the K2 to stabilize for at least 10 minutes at room temperature approx 20 25 Note Avoid using a high wattage work lamp direct above the K2 during calibration With the top cover removed this could heat the RF board to a higher temperature than would ever be seen during normal operation Connect the internal frequency counter cable to the VCO output test point Use the procedure listed below to linearize the VFO If you see any INFO messages refer to Troubleshooting 1 Use BAND to select 40 meters Select CW normal mode and filter 2 Set the VFO to anywhere in the range 7000 7100 kHz 3 Enter the menu and select CAL PLL then hold a second time to start the VFO linearization sequence 4 The frequency counter will show the VCO frequency as it decreases through a range of about 10 13 kHz The letter d will flash each time a calibration data point 1 stored 5 When calibration 1s completed 4 8 minutes you ll see the message End on the LCD You can then tap any switch to return to normal operation If you see an INFO message rather than End refer to Troubleshooting Appendix E 64 Amplifier Alignment L34 located near the right front corner of the
112. T 25LC320 U10 LMC660 Check the orientation of pin 1 on each IC by looking at associated PC board pads as before Then solder all of the ICs L Locate the microcontroller U6 Straighten the pins of U6 see Figure 4 9 With a large IC such as this you can hold the IC body at both ends as you re form each row of pins AN When the microcontroller is pressed in its socket you must be careful to avoid jamming its pins Make sure that all pins are lined up with the associated holes in the socket before pressing down on the IC Watch the pins on both rows as you press down re aligning them with the socket holes individually if necessary LJ Insert the microcontroller U6 into its socket Make sure that pin 1 on the IC itself is lined up with the pin 1 label near the lower left hand corner of the PCB outline Note The revision label on the IC usually white may not be oriented the same direction as the text printed on the IC Do not use the label as a guide use the notch or dimple to identify pin 1 ELECRAFT 20 Key Shaping Components Required Your K2 kit includes recent changes that provide an optimized keying envelope shape sigmoidal or S shaped leading and trailing edges The result is completely click free CW transmission Two of the parts for this change must be installed on the back of the Control board as described below Locate green insulated hookup wire Strip two 1 4 6 4 mm
113. WPM 95 Internal Keyer To use a keyer paddle use the menu to choose INP PDLn or INP PDLr normal or reverse paddle With PDLn selected the tip contact on the stereo key jack is DOT and ring the middle contact is DASH PDLr is the reverse External Keying Auto Detect If you wish to connect a handkey external keyer or computer along with a keyer paddle you can use the K2 s auto detect feature Simply connect your external keying device to the DOT and DASH lines through two diodes as shown Figure 8 1 along with the keyer paddle Be sure you have selected INP PDLn or INP PDLR in the menu TO K2 KEY JACK GROUND HANDKEY COMPUTER OR EXTERNAL KEYER Figure 8 1 When you connect the keying devices in this way you can continue to use the paddle as usual But if the external keying device 1s keyed both the DOT and DASH lines will be pulled low simultaneously via the diodes The K2 firmware interprets this as direct external keying rather than as DOT or DASH triggers Auto Detect can be turned off if desired Find the INP menu entry the parameter then tap DISPLAY to select ADET OFF 96 Basic CW Setup Mode Selection To place the rig in CW mode tap the MODE switch until the mode indicator changes to C Filter Selection Select a crystal filter using the X FIL switch FL1 is usually configured as the widest filter Similarly use to select an audio filter requires KAF2 or K
114. a 2 or 3 V DC volts range Xmit Mixer Output Measure the key down signal at U10 pin 4 Expected 0 016 Vrms Actual Buffer Output Measure the key down signal at U9 pin 6 LT1252 Expected 0 200 Vrms Actual Band Pass Filter Output Measure the key down signal at W6 Expected 0 030 Vrms Actual T R Switch 1 Output Measure the key down signal at the anode of D1 Expected 0 029 Vrms Actual Pre driver Driver and PA RF sheet 4 1 Pre Driver Output Measure the key down signal at the case collector of Q5 2N5109 Expected 0 120 Vrms Actual 14 2 Driver Input Measure the key down signal on the base of Q6 2SC2166 pins are labeled B C E Expected 0 026 Vrms Actual 3 Driver Output Measure the key down signal at the tab collector of Q6 Expected 1 8 Vrms Actual 4 Input Q7 Measure the key down signal at the base of Q7 2SC1969 on bottom of the board pins are labeled on the top Expected 0 38 Vrms Actual 5 PA Input Q8 Measure the key down signal at the base of Q8 Expected 0 38 Vrms Actual 6 RF Detector Input Measure the key down signal on the anode non banded end of D9 1N5711 middle of the right edge of the board Expected 2 0 Vrms Actual This voltage should be fairly constant regardless of the band used 7 PA Transistor Tests If the PA input voltages were higher than expected but the RF detector input was too low one or both PA transistors c
115. air of headphones and key paddle set the POWER control fully counter clockwise minimum power output Turn on K2 You should see ELECRAFT LCD followed by the frequency display ELECRAFT Select voltage current display mode by tapping DISPLAY to make sure the receiver 1s not drawing excess current Typical current drain will be 180 250 mA depending on menu settings Return to frequency display mode Switch to CW and select FL1 using X FIL Use menu to set up desired CW sidetone volume and pitch if you have not already done so using ST L and ST P The pitch can be set from 400 to 800 Hz although 500 600 Hz 15 recommended The sidetone volume and tone will vary a small amount as the pitch is changed but it should have a pleasant sinewave sound at any setting LJ set up the desired keying device using INP If you re using a hand key or external keyer use INP HAND To use the internal keyer select PDLn or PDLr normal or reverse paddle You can also connect a computer or external keyer along with the keyer paddle Refer to the Operation section for details on this auto detect feature Page 95 To verify that the sidetone is functioning hold switch Tap any switch to turn the SPOT tone off ELECRAFT 40 Meter Transmitter Alignment AN To align the transmitter you ll need some means for monitoring power output as you ad
116. all of the pins at the body first then remove all of the pins slowly one at a time You may damage pads and traces by trying to remove a component intact possibly leaving a PC board very difficult to repair Invest in a PC board vice with a heavy base if possible This makes parts removal easier because it frees up both hands If in doubt about a particular repair ask for advice from Elecraft or from a someone else with PCB repair experience Our e mail reflector is also an excellent source for help ELECRAFT 4 Control Board The Control board is the brain of the K2 It monitors all signals during receive and transmit and handles display and control functions via the Front Panel board The microcontroller analog and digital control circuits automatic gain control AGC and audio amplifier are located on this board Components AN Review the precautions described in the previous section before handling any IC s or transistors These components can be damaged by static discharge and the resulting problems are often difficult to troubleshoot Open the bag of components labeled CONTROL and sort the parts into groups resistors diodes capacitors etc If any of the components are unfamiliar identify them using the illustrations in the parts list Appendix A L Locate the Control board It is the smallest of the three K2 PC boards labeled K2 CONTROL on the front side in the lower right hand corner The
117. all of the remaining capacitors by value to reduce the possibility of assembly errors in the next step If you are unsure of any capacitor s value and do not have a capacitance meter the pictures in the parts list Appendix A may help Install the following capacitors starting with C86 in front left corner Integer values are pF and fractional values are in uF __ 86 0 1 104 84 120 121 C85 120 121 C100 001 102 C95 01 103 7 C96 1 uF 105 C71 82 82 7 092 270 271 CB 47 47 7 C74 20 20 C82 001 102 7 C79 001 102 C55 01 103 7 C65 0 1 104 __ C80 001 102 C59 0 1 104 C61 01 103 C54 01 103 C81 001 102 C38 001 102 7 C58 01 103 2 68 10 pF 10 C63 01 103 7 C89 001 102 C62 01 103 2 64 001 102 C92 022 223 C87 01 103 7 C154 100 101 __ C67 0 1 104 7 C94 0 047 473 7 C175 01 103 CIA4 100 101 C156 047 473 C52 01 103 2158 01 103 C141 01 103 __ C53 01 103 C57 001 102 7 C146 01 103 7 C151 0 1 104 7 145 01 103 7 153 68 68 7 C155 01 103 CI72 01 103 2177 022 223 2 CI74 82 82 CI73 220 221 7 CI78 0 1 104 176 0 1 104 C165 01 103 7 C169 390 391 7 168 01 103 7 C160 01 103 7 C159 01 103 7 C143 01 103 C122 01 103
118. all rectangular black key caps on remaining switches AN Before handling U1 touch an unpainted grounded metal surface or put on a conductive wrist strap Straighten the pins of U1 the LCD driver PCF8566 as you did with the microcontroller on the Control board Insert U1 into its socket on the bottom of the board This must be done before continuing with LCD installation since the LCD s presence will make pressing U1 into its socket much more difficult Be sure that Ul is completely seated with no bent pins Locate the LCD backlight assembly which 1 about 3 7 5 cm long It includes the diffuser and two small LEDs one at each end Do not remove the backing from either side of the diffuser Make sure the LEDs in the LCD backlight assembly are pressed into the diffuser and are not mis aligned or loose Place two 3 4 19 mm long spacers over the leads of each backlight LED as shown in Figure 5 9 ELECRAFT a diffuser spacers 2 Figure 5 9 Position backlight assembly between mounting holes labeled D2 and D3 as shown in Figure 5 10 The diffuser must be parallel to and 1 8 3 mm above the PC board To hold the LED spacers and backlight assembly in place use a rubber band or bend the LED leads out slightly on either end spacers 2 diffuser Figure 5 10 ELECRAFT Examine the backlight assembly closely to ensure that it 1s parallel to the Front Panel
119. and These commands are transmitted on a one wire network called the AuxBus The AuxBus network line sits at a logic high during normal operation and is only activated when needed The receiver is muted during commands so the operator never hears any digital noise due to AuxBus activity Most AuxBus transmissions occur due to operator requests such as a band change However the AuxBus may also be used during transmit to relay numeric data such as SWR or ALC from a coprocessor to the main microcontroller Waking up the coprocessors during transmit has no effect on the transmitted signal ELECRAFT Front Panel Board The front panel PC board plugs into the RF board via a 20 pin single row connector P1 The Front Panel is made up of a number of user interface elements as detailed below The LCD DS1 is an 8 digit 7 segment transflective type with three backplanes triplexed Its driver U1 receives display commands via an C interface The LCD backlight LEDs D2 and D3 are used to provide enough brightness to handle low lighting situations NITE mode in the menu while drawing only a small amount of current lt 30 mA However they can be turned off when ambient lighting is sufficient DAY mode because the LCD 1 transflective 1 e it can either reflect or transmit light The LCD displays the operating frequency and status messages and also has 8 annunciators which indicate the settings of various controls A 10 segment
120. and L11 for maximum signal strength Switch to 17 meters 18100 kHz and turn preamp Adjust C32 and C34 for maximum signal strength Switch to 10 meters 28200 kHz and turn preamp Adjust L12 and L13 for maximum signal strength Switch to 12 meters 24900 kHz and turn preamp Adjust C44 and C46 for maximum signal strength This completes receiver alignment AN During receiver alignment you may have noticed that signal strength is somewhat lower in volume when you select the narrowest filter 100 Hz setting FL4 This is because the K2 s crystal filter 15 optimized for wider bandwidths 250 800 Hz Despite the slightly greater attenuation the narrower settings are very useful in reducing QRM interference from strong nearby signals Any of the filter settings can be changed and FL2 FL4 can even be turned OFF See page 88 for information on customizing filter settings ELECRAFT 77 Transmitter Alignment If you did the receiver alignment above you may find that little or N Since some inductors are shared between two bands you no transmit adjustment is required on most bands must always align the remaining bands in the order indicated Always use this procedure if you re align the filters later Set the POWER control for 2 0 watts Switch to 20 meters 14100 kHz Set C21 and C23 to their Switch to 80 meters and set the VFO for about 3750 kHz mid points A
121. and hope it meets your expectations for operation both at home and in the field Wayne Burdick NOKR Eric Swartz WA6HHQ Pre Wound Toroids Available You can obtain a set of pre wound toroids for the K2 if you prefer not to wind them yourself Refer to our web site for details Customer Service Information Technical Assistance If you have difficulty with kit construction operation or troubleshooting we re here to help You may be able to save time by first consulting our web site www elecraft com or by posting your question on our e mail forum elecraft mailman gth net Telephone assistance 15 available from 9 A M to 5 P M Pacific time weekdays at 831 662 8345 Via e mail use support elecraft com for support and parts elecraft com to request replacement parts Please use e mail when possible this gives us a written record of the details of your problem Repair Service If necessary you may return your completed kit to us for repair Contact Elecraft before mailing your kit to obtain current information on repair fees Kits that have been soldered using acid core solder water soluble flux solder or other corrosive or conductive fluxes or solvents cannot be accepted for repair The following information should be provided to expedite repair your name address and phone number your e mail address if applicable and a complete description of the problem Shipping First seal the unit a plastic bag t
122. and recall Best of all it includes an integral dual antenna switch controlled by 1 2 providing the functionality of two antenna tuners in one The uses latching relays so current drain 15 nearly zero except when an antenna is being tuned KAT100 High Power Automatic Antenna Tuner ATU The KAT100 is a rugged external ATU that s the ideal companion for the K2 100 It can handle up to 150 watts and like the KAT2 provides two antenna jacks accessible with 1 2 switch The KAT100 offers the same matching range menu control features and display capabilities of the KAT2 and in addition offers 10 LEDs for real time monitoring of SWR Note The KAT100 can be used with the basic K2 as well as the K2 100 The basic K2 must have the KIO2 option installed to control the tuner 113 K60XV 60 m Adapter and Transverter Interface The K60XV adds 60 meter coverage and low level split RX TX transverter interface 0 dBm K160RX 160 m Adapter and RX ANT Switch The K160RX option adds 160 meters a separate receive antenna switch The receive antenna can have a separate preamp attenuator setting from the normal antenna per band KBT2 Internal 12 V Battery The rechargeable battery fits snugly into the top cover along with the KAT2 ATU and or KIO2 Recharging requires an external 14 V regulated power supply which can also power the transceiver KIO2 RS232 Interface This option allows full computer
123. ap again within 5 seconds or less each time This will reduce the chance of damaging any components in the transmitter that are consuming excess power l 25 Ua Switch to voltage current display mode using DISPLAY Hold to key the transmitter and verify that supply voltage does not drop by more than about 0 8 V If it drops more than this either your power supply is inadequate or the transmitter is drawing excess current Actual transmit mode voltage V Current A Return to normal display mode using DISPLAY Measure the key down DC voltages on the anodes right end of D6 and D7 near U1 the I O controller During transmit the voltage on the anode of D7 should be about 8 V and on D6 near 0 V Actual TX mode voltages D6 V D7 V Use and note the actual power output W 13 Sidetone Control Board Note If the sidetone 15 already functioning correctly you can skip this section 1 Make sure you re in CW mode The sidetone will not function in SSB modes 2 Disconnect the headphones and speaker Use the menu to set ST L to 255 maximum sidetone level 4 Usethe button to select CW TEST mode the mode letter will then flash This 1s a safe setting for sidetone tests since there 1s no power output 5 Set your DMM for AC volts 2 or 3 V range Touch the positive lead of the DMM to pin 25 of U6 on the control board 18C452 This is the source of the sidetone signal
124. arge size of resistor R62 resulting in approximately a class B bias level On SSB resistor R63 is grounded by the I O controller causing much more current flow through Q13 and stabilizing the bias for class AB operation ELECRAFT 10 Options The K2 can be customized using a variety of internal and external options which are briefly described here Note If you press a switch associated with a missing option module you ll see NOT INST not installed on the LCD Menu parameters for missing options will be displayed as KSB2 SSB Adapter The KSB2 allows the K2 to transmit and receive LSB and USB which enables use of voice as well as PSK31 RTTY AFSK SSTV and other data modes VOX and PTT are supported and power output can be set from about 0 5 to 15 watts PEP The adapter s crystal filter is optimized for SSB transmit and receive but can also be used for CW or AM receive Mic gain and speech compression level can be set using the menu Our MH2 Heil Elecraft hand mic is ideally suited to use with the KSB2 KNB2 Noise Blanker The KNB2 is effective on a wide range of noise sources and includes two gain settings as well as two different blanking pulse widths The noise blanker 15 controlled using two dedicated front panel functions and 3138 KAT2 Automatic Antenna Tuner ATU Our internal ATU handles a wide range of impedances tunes nearly any antenna on any band in seconds and stores all data for instant b
125. atic antenna tuner and RS 232 interface The top cover can be replaced with a 100 W power amplifier module converting the K2 into a medium power station ELECRAFT Signal Flow The block diagram Appendix C shows overall signal flow in the K2 Transmit and receive paths are shown for sideband operation For CW transmit the BFO signal is routed directly to the transmit mixer The K2 receiver is a single conversion superhet utilizing double tuned band pass filters on each band and down conversion to a low 4 915 MHz This approach results in excellent CW and SSB performance The low is compatible with narrow variable bandwidth CW crystal filtering and allows the use of fast I F derived AGC An of 4 915 MHz also results in nearly no birdies across all nine bands The BFO 1 microcontroller controlled to allow upper and lower sideband reception on any band as well as CW on either sideband AM signals can be received in SSB modes thanks to the stable VFO although AM transmit 1 not currently supported Individual per band band pass filters offer improved intermodulation performance when compared to up conversion designs that use only a single low pass filter to remove image products ahead of the receiver Up conversion also requires the use of a second to obtain good CW performance increasing cost and producing additional spurious signals An alternative is up conversion followed directly by a product detec
126. ats 4 RE Pais RFbowdpat Bag Contelboard paris essooo2 E Bag Mee Pas Hardware and Wise parsJessoooa K2 K3 K4 K5 K7 K9 K10 K11 K12 K13 K14 K15 K16 K17 Latching Relay 5V In plastic tube 10 pin DIP E640001 17 Manual JE740001 4 ohm 3 watt high sensitivity speaker E980007 1 Knob 1 6 diam Main Tuning Knob weighted 6mm shaft E980013 1 9 1 KN2 KN3 KN4 KN5 KN6 Knob 0 5 diam Small Control Knobs 6mm shaft E980016 Docs Toroid Order Form E740038 Page 1 Box and Serial Appendix A Items inside back of manual E850011 PICTURE Designators Value Description Part Number QTY Covers LCD and LED bargraph FRONT Misc Acrylic display bezel PANEL E100080 Thermal insulator Adhesive Thermal Insulators for Q6 Q7 Q8 HW TO220 RF BOARD E700002 S Serial Number Label _ 4 1 15 x 0 95 with adhesive strips FRONT Misc Green filter w adhesive PANEL E98001 1 Page 2 Box and Serial Appendix K2 Control Board Parts List p n 50002 PICTURE Designators Value Description Part Number QTY C2 C20 C34 C43 001 Monolithic 102 530001 4 C12 C24 C36 C3 C5 C9 C11 C17 C18 C23 C31 C35 C37 C39 C41 C46 01 Monolithic o dp 103 E530009 15 C27 jue ss 1 C6 C14 C16 C19 C30 Monolithic ic Cap 473 530025 5 C25
127. band page 100 calibration submenu page 87 programmable functions page 100 can be assigned to any menu function SCAN or FPon Fast Play If auto detect is turned on a computer hand key or external keyer can be connected along with the paddle See page 95 ELECRAFT Calibration Functions The CAL menu provides the following functions FCTR Frequency counter CUR Programmable transmit current limit TPA PA temperature set see 100 manual S LO S meter zero set S HI S meter full scale sensitivity set PLL VFO linearization FIL Filter settings see next page After selecting a CAL function hold to activate it Frequency Counter CAL FCTR CAL FCTR displays the frequency of the signal at P6 on the Control board during alignment see page 60 Transmit Current Limit CAL CUR CAL CUR allows you to set a safe maximum transmit current The recommended setting 1s 3 50 A A lower setting may be appropriate if you re using 5 watts or less or your power supply has a lower current rating S meter Calibration CAL S LO CAL S HI To set the S meter zero level Disconnect the antenna Make sure the RF GAIN control is fully clockwise max gain Select CAL S LO in the menu Turn the VFO knob until the left most bargraph segment is just barely turned off 5 Exit CAL mode by tapping MENU WN 87 set S meter sensitivity 1 Disconnect the antenna Turn the RF GAIN c
128. be adjusted later to suite the operator AN The S meter must be realigned anytime the AGC threshold setting is changed S meter alignment is covered in the following steps S Meter Alignment Using the menu select the CAL S LO function S meter zero Hold 8 a second time to activate it Turn the VFO knob until you see only the left most segment of the LED bargraph lit Then turn the knob a bit more clockwise until this LED just turns off Exit the CAL S LO function by tapping MENU Enter the menu again and select CAL S HI S meter full scale sensitivity Turn RF GAIN fully counter clockwise Adjust VFO knob until bargraph segment 9 lights then turn it a bit more counter clockwise until segment 10 just turns on right most segment Turn RF GAIN control back to its clockwise position 47 Exit the CAL S HI function by tapping MENU If you have an Elecraft receiver test oscillator or other calibrated signal source set it for 50 microvolts 73 dBm and verify that the S meter indicates S 9 If not adjust CAL S Bargraph Current Test In the following steps you ll test the current measurement circuit by using the bargraph LEDs to establish a known current drain Enter the menu and verify that GRPH LED bargraph mode is set to DOT not to BAR or OFF Set the RF GAIN control for minimum gain Segment 10 of the LED bargraph should now be on if y
129. careful power control at all stages in the transceiver results in receive mode current drain as low as 100 mA The latching relays are all controlled by a single device the I O Controller see below which also handles other miscellaneous I O tasks on the RF board DPDT relays are used for all filter switching reducing the number of relays needed by a factor of two 50 ohm switching is used for all filters and this combined with careful layout and guard banding of the relays results in excellent filter input output isolation Co Processors and the AuxBus In keeping with the K2 s modular system architecture much of the I O switching is handled by co processors There is only one co processor the basic K2 the I O Controller JOC Some option modules such as the SSB adapter have their own co processors This distributed processing technique allows future modifications to be made to option boards without changing the transceiver itself It also reduces cost of the basic K2 since fewer main processor control lines are needed The IOC as well as all co processors on option modules go into sleep mode with their own 4 MHz clocks suspended during normal operation For this reason there is virtually no digital noise on the RF board to cause receiver EMI When the operator performs an operation that changes relay states the main microcontroller on the Control board wakes up the co processors and sends one of them a configuration comm
130. causing a short on a regulated supply line Make sure that the DC input voltage at J3 1s gt 8 5 the minimum voltage needed by the voltage regulators If 5V is too low lt 4 5V go to 052 If 8V is too low lt 7 5V go to 053 Check all DC voltages using the voltage tables later in this section Start with the control board If the problem involves the front panel measure those voltages next If the problem is with T R switching check the RF board voltages next You may have RP2 on the front panel board installed backwards Remove the front panel to see if it is was pulling the 5V line low If not the problem is likely to be on the control board Pull the control board out and inspect the entire 5V line looking for heat damaged components or shorts The schematic can be used to identify components on the 5V line Remove the microprocessor to see if it is loading the 5V line down Unsolder the output pin of the 5V regulator and bend it up slightly to break contact with the PC board If the voltage 1 still too low measured at the pin replace the regulator 053 8V too low 7 5V Inspect the entire 8V path on the RF and control boards Look for heat damaged components or solder bridges Unsolder the output pin of the 8V regulator and bend it up slightly to break contact with the PC board If the voltage 1 still too low measured at the pin replace the regulator There are a number of places where you can easil
131. ced Operating Features page 99 Antenna Selection If you re using or KAT100 automatic antenna tuner the ANT 1 2 switch will toggle between the two ATU antenna jacks This also instantly recalls the ATU s stored L C parameters for each antenna Refer to the relevant ATU manual Noise Blanker Controls The KNB2 option is required to use these controls The noise blanker is always turned OFF on power up and you should leave it off unless needed When it 1 turned on the receiver will be more susceptible to interference from strong signals To turn on the noise blanker tap the switch You ll see NB1 NB2 and OFF in that order The NB1 and NB2 modes provide short or wide pulse blanking intervals respectively One may be more effective than the other depending on the type of noise In either mode the NB annunciator will turn on The noise blanker provides two thresholds of noise detection high and low If you hold the noise blanker will toggle between these two modes with the display showing HI THR or LO THR High threshold is the default and should be used in most cases If you select low threshold the noise blanker may be more effective on certain types of noise but it will also leave the receiver more vulnerable to strong in band signals When LO THR is selected the NB annunciator flashes as a reminder ELECRAFT LCD and Bargraph Configuration Day Night Selection For daytime outdoor
132. ching them Place speaker top of fibre washers and grille cloth Secure it with four 3 8 9 5 mm screws 4 lock washers and 4 40 nuts Figure 7 2 Do not over tighten the nuts Top Cover Figure 7 2 Locate two holes marked A in Figure 7 1 Use two 4 40 x 3 8 9 5 mm screws to fill these holes securing them with 4 lock washers and 4 40 nuts The holes are for the battery option Install 2 D fasteners at the two locations marked B in Figure 7 1 The 2 D fasteners should line up exactly with the edges Use two chassis screws per 2 D fastener ELECRAFT Using a sharp tool cut through and peel off about 1 2 x 1 2 12 x 12 mm of the masking material covering the EXT SPKR hole Note Leave the other holes covered with masking material until the associated options are installed LJ Install the external speaker jack in the EXT SPKR hole Orient the jack as shown in Figure 7 1 and Figure 7 4 with the tab nearest the inside of the top cover Caution Mis identification of the three tabs could result in a ground short LJ 24 61 cm of 2 conductor speaker cable 15 supplied Cut it into two pieces 15 38 cm and 9 23 cm long LJ solder crimp pins to the two wires at one end of the 15 38 cm length of speaker cable Figure 7 3 Copper wire Pin side Hous Crimp pin Figure 7 3 AN When you insert crimp pins into the housing in the next step they shou
133. components to be installed so you won t need to refer to the parts list during assembly The order that the components are installed corresponds to their PCB locations Do not skip any assembly steps you may find that you ve installed one component that hinders the installation of another Forming component leads In a few cases you ll find that the space provided for a component on the PC board 1 larger than the distance between the leads on the part itself In such cases you ll need to carefully bend the leads out and then down to fit the given space Always use needle nose pliers to accomplish this task and bend the leads don t tug on them This is especially important with capacitor leads which are fragile Bottom Mounted Components A number of components in the K2 are mounted on the bottom of the PC boards to improve component spacing or for electrical reasons Component outline symbols are provided on both sides of each board so it will always be clear which side a particular component goes on You ll be able to tell the top of the board from the bottom easily the top side has far more parts Bottom mounted parts are identified on the schematic by this symbol EY Top bottom interference In a few cases top mounted parts may interfere with the trimming and soldering of a bottom mounted part In this case pre trim the leads of the bottom mounted part before final placement and solder it on the bottom rather than on
134. con diodes with a PIN characteristic 1N4007 Q2 is a very high voltage MOSFET that provides a ground path on receive for D3 and D4 but on transmit this transistor can easily handle the high voltages present on the power amplifier collectors 28 PIC microcontroller 16F872 or 16F872A drives all of the latching relays and a few other I O lines U1 15 referred to it as the I O controller IOC because it handles nearly all I O functions for the main microcontroller It also has the job of determining whether the 160 m RXANT option board is installed by sensing the presence or absence of the two relays on the module Finally the IOC contains all of the per band and per memory initialization data in ROM which 1 sent to the main microcontroller as needed to initialize EEPROM data tables A number of different regional band plans and other customized parameters can be accommodated in U1 s data tables ELECRAFT The latching relays are wired with a single common drive line so that when one relay needs to be turned on or off the others are pulled in the opposite direction This arrangement requires no drivers of any kind U1 s I O lines are protected from relay transients by its own internal shottky clamping diodes to 6 V and ground Measured transients are well within the current rating of the clamping diodes Transients are reduced in amplitude by the series resistance of the other non switched relays and U1 s own MOSFET drive
135. d You can also select a wider RIT XIT range see RIT menu entry page 104 As in many transceivers this control actually varies gain ELECRAFT Switch Functions Each pushbutton switch as two primary functions indicated by the upper and lower labels a switch to access its upper function a e 8 a switch for over 1 2 second to access its lower function Numeric Keypad In addition to their tap hold functions ten of the switches are labeled with digits 0 through 9 A digit can be entered using either a TAP or HOLD e g 5 or 5 In some cases the difference between the two is significant as indicated below Tap and Hold Functions gt gt 2 12 5 E A m m z c m DISPLAY A n gt s O I gt 2 Z m N m lt m E gt m O O A m 740 select next higher band recall memory 0 9 to start scan use 3 select next lower band store memory 0H9 to start scan use 4 4 enter the menu edit current menu parameter show voltage current time DSP parameters select SSB transmit bargraph mode RF or ALC toggle between ATU antenna jacks 1 and 2 key transmitter activates ATU if installed select noise blanker mode OFF NB1 NB2 toggle noise blanker threshold low or high select VFO tuning rate see RATE
136. de Figure 4 2 16 LJ Install Q12 near the upper left hand corner of the PC board Align the large flat side of Q12 with its PC board outline as in Figure 4 2 The body of the transistor should be about 1 8 3 mm above the board don t force it down too far or you may break the leads Bend the leads of the transistor outward slightly on the bottom to hold it in place Solder Q12 Install the remaining TO 92 package transistors in the order listed below QILPN222A Q1 2N3906 02 243906 03 2N7000 04 2N7000 05 2N7000 Q6 2310 Q7 310 Q8 PN2222A 09 MPS5179 7 010 MPS5179 Solder and trim the leads of these transistors Install crystals X1 and X2 so that they are flat against the board X1 1s 5 068 MHz and 1 located near the notch in the lower left hand corner X2 is 4 000 MHz and is located near the center of the board Solder crystals Prepare two 3 4 19 mm jumpers wires from discarded component leads These short jumpers will be used to ground the crystal cans in the next step A Grounding the crystal cans in the following step is required to ensure proper crystal oscillator performance Referring to Figure 4 3 insert the jumper wires into the grounding holes provided near X1 and X2 Fold each wire over the top of the crystal and solder it to the top of the can Only a small amount of solder 1s required Then solder and trim the wire on the bottom o
137. ding using 5 turns of green enamel wire 6 15 em Strip and tin the leads of both windings Figure 6 18 Install T7 as shown by its component outline near the front right corner of the board with the windings oriented as shown in Figure 6 18 Pull the leads taut on the bottom and solder 56 Transformer T6 is mounted vertically near the middle of the board It uses a different winding technique where the wires for the two windings are twisted together before winding bi filar Cut two 12 30 cm lengths of enamel wire one red and one green Twist them together over their entire length The wires should cross over each other about once every 1 2 or 12 mm Wind the twisted wires onto a 3 8 9 5 mm ferrite core FT37 43 using exactly 10 turns Use the same method you used when winding non twisted wires covering about 85 of the core Figure 6 19 shows how the winding should look from two views your turns count will be 10 rather than 8 as in the drawing RED Figure 6 19 ELECRAFT Clip and untwist the ends of the red green pairs so that the leads of the transformer look like those in Figure 6 19 b The pin numbers shown match the component outline with the red wires numbered 1 3 and the green wires numbered 2 4 Strip and tin all four wires Be careful not to strip leads so close to the core that the red green wire pairs might short together Install T6 vertically with wire
138. djust L8 and L9 for maximum power output This mid band step pre sets C21 C23 L8 and L9 before final adjustment in the next two steps Enter tune mode and adjust 13 and 14 maximum power indicated on the internal wattmeter Use a more sensitive analog Switch to 30 meters 10100 kHz and adjust L8 and L9 for instrument if available Limit tune up time to 5 or 10 seconds maximum power output Switch to 20 meters 14100 kHz and adjust C21 and C23 for maximum power output Switch to 15 meters 21100 kHz and adjust L10 and L11 for maximum power output Switch to 17 meters 18100 kHz and adjust C32 and C34 for maximum power output Switch to 10 meters 28200 kHz and adjust L12 and L13 for maximum power output Switch to 12 meters 24900 kHz and adjust C44 and C46 for maximum power output This completes transmitter alignment 78 7 Final Assembly Place the top cover upside down as shown in Figure 7 1 with its rear panel facing away from you The illustration shows how the speaker 2 conductor cable external speaker jack and other hardware will be attached to the top cover D Figure 7 1 ELECRAFT Trim supplied grille cloth to size of speaker frame L Place 4 fibre washers black at each of the top cover s four speaker mounting holes Figure 7 1 Trim the corners of the grille cloth so it just fits between the fibre washers not tou
139. ds after completing each group A final complete check will be done later Remove the screws holding the Control board to the Front Panel board then unplug the Control board To avoid damaging any Control board components use the long handled Allen wrench as described in Part I Remove the bottom cover six screws Remove the screws from the front panel assembly and unplug it from the RF board Pull it straight out from the bottom edge near the middle of the panel This may be easier to do with the transceiver sitting on its right side so that you can steady it with one hand and pull with the other Remove the side panels by taking out the two screws along the bottom edge of each panel Install the following 1 4 watt resistors orienting them so that the first band is at the left or toward the back of the board The resistors are listed the order they appear on the RF board starting with R9 near the left edge about halfway back Note Remember to complete each line of resistors before proceeding to the next line 1 e install R9 then R16 then R10 ELECRAFT R9 100 k BRN BLK YEL _ R16 100 BRN BLK YEL R10 470 YEL VIO BRN R31 10 BRN BLK ORG R32 10k BRN BLK ORG R33 15 BRN GRN ORG R30 120 BRN RED BRN R28 27k RED VIO ORG 820 270 RED VIO BRN R21 100 BRN BLK YEL R22 3 3 ORG ORG GRN __ 25 2 7 RED VIO RED R24 2 7 RED VIO RE
140. e or 2 HOLD one of these switches to activate the selected menu shortcut then change the menu parameter which will be underlined using the VFO knob or To return to normal operation tap any switch or the keyer paddle Exceptions the FPon SCAN and RANT functions take effect immediately Using PF1 or PF2 as secondary menu shortcuts Enter the menu and scroll to PF1 or PF2 To switch to the secondary menu entries tap DISPLAY Tapping DISPLAY again will return to the primary menu entries Select the desired parameter then exit the menu AGC On Off Control Some operators prefer to turn AGC off and use manual RF GAIN control under certain weak signal conditions To turn off AGC Hold both the P RE ATT and switches simultaneously Release the switches when you see OFF flashed on the LCD To remind you that AGC 15 off the decimal point to the left of the mode indicator will flash slowly Received signals will no longer affect the S meter level Turning the RF GAIN control counter clockwise will increase the S meter reading ELECRAFT Frequency Calibration Techniques The VFO 15 only as accurate as the 4 000 MHz oscillator on the Control board which is calibrated using C22 C22 can be fine tuned using one of the following methods Using an External Counter or Ham Band Receiver These methods are described in detail in Alignment Part 4 MHz
141. e in contact with the transistor 4 40 screw Thermal Pad Figure 6 32 Back out mounting screws for Q7 and Q8 until ends of the screws protrude only slightly from the transistor tabs Keep the K2 on its left side so the screws don t slip out further L Make sure that the thermal pads on Q7 and Q8 are centered and that you can see the shoulder washers inside the tab holes If the shoulder washers have come out of the tab holes re align the PA transistor hardware as needed ELECRAFT Keeping K2 on its left side slip heat sink over rear panel connectors and into position Figure 6 33 Figure 6 34 shows how the heat sink and associated hardware appear in cross section Figure 6 33 Make sure that the four small holes in the heat sink line up with 07 08 and the 2 D block between them Press the 07 08 mounting screws all the way back in so that they protrude from the heat sink Use two chassis screws and two 4 lock washers to secure the heat sink firmly to the 2 D fastener 73 Secure Q7 and Q8 the bottom of heat sink using 4 40 nuts and 4 lock washers Do not over tighten the nuts as this may cause the thermal pads to scrape against the heat sink possibly causing a short to ground Figure 6 34 Using an ohmmeter on a low resistance scale check for a short from Q7 or Q8 collector to ground This test should also be performed any time t
142. e reference oscillator for the PLL IC is temperature compensated by the components on the thermistor PC board This circuit works by applying a variable offset voltage to varactor diodes D16 and D17 to compensate for drift As temperature increases the uncompensated oscillator would drift down in frequency The thermistor causes a slight increase in the bias voltage to these diodes as the temperature increases The relative values of RA RD and the thermistor Rt see below set the rate of gain change with temperature ELECRAFT U4 provides coarse tuning 5 kHz steps Fine steps are achieved using a 12 bit DAC 05 to tune a voltage controlled crystal oscillator 019 which is the PLL reference oscillator The reference oscillator range needed on each band varies in proportion to the VCO output frequency To cover exactly 5 kHz in 10 Hz steps on each band an automatic calibration routine is provided in firmware The DAC is swept from its highest output voltage down and the DAC word needed to select each 100 Hz step is recorded in EEPROM on a per band basis 10 Hz steps are then interpolated based on the 100 Hz table data Crystal X1 in the PLL reference oscillator can be tuned by varactor diodes D16 and D17 over a range of about 10 kHz which is required in order to tune the full 5 kHz on the lowest band 160 m but still provides better than 10 Hz resolution on the highest bands The synthesizer design is unique that three inexpensive DPDT
143. e signals 1 determined by the BFO beat frequency oscillator Figure 9 1 shows an example of how these signals are related The BFO frequency is below the filter passband this 1s the case for the CW normal and LSB modes on the K2 Two different filters are shown FL2 narrow for CW and FL1 wide for LSB voice Frequencies in the 4915 kHz range are shown because this is the K2 s intermediate frequency or 4913 0 4913 5 4914 0 4914 5 4915 0 Signal 1 Signal 2 Figure 9 1 CW Normal or LSB In this example filter FL2 s bandwidth 1 set for about 1 kHz and it 1 centered at 4914 0 kHz The BFO 1s set for 4913 0 kHz Signal 1 4914 0 kHz will be passed by FL2 and you ll hear it at an audio pitch of 1 kHz 4914 4913 Signal 2 4915 0 kHz will be rejected by FL2 but passed by FL1 and heard at 2 kHz The same BFO setting can be used for both filters because the lower boundary of the K2 s variable bandwidth crystal filter stays fixed as it is made wider Only the upper edge moves significantly 107 Figure 9 2 shows the BFO positioned above the same two filters which will allow the K2 to receive USB and CW Reverse opposite sideband CW Since the upper boundary of the filter moves as the filter is widened the BFO frequency must move the same amount BFO2 is used with FL2 and is used with 4913 5 4914 0 4914 5 4915 0 4915 5 BFO2 BFOI Figure 9 2 CW Reverse or USB The CA
144. e the placement of the connector If P1 is not flat against the board re heat the solder on the end pins one at a time while pressing firmly on the connector Once it 1s the right position solder all pins Do not trim the leads ELECRAFT Top side of PC Board P3 Figure 4 8 Install P3 the 20 pin dual row right angle connector Figure 4 8 Use the same method you used for P1 Do not solder P3 until you are sure that it is seated properly Install P2 36 pin dual row right angle connector Use same method you used for P1 and P3 AN When you install ICs in the following steps always straighten the leads of each IC first as shown in Figure 4 9 The two rows of pins must be straight and parallel to each other to establish the proper pin spacing for insertion into the PC board or socket To straighten the pins rest one entire row of pins against a hard flat surface Press down gently on the other row of pins and rock the IC forward to bend the pins into position as shown below Flared Straight Figure 4 9 ELECRAFT AN Before handling any IC touch an unpainted grounded metal surface or put on a conductive wrist strap Locate U2 an 8 pin IC part number LM833 LM 833 is the basic part number There may be an additional prefix or suffix or other markings This and all remaining ICs on the Control board are Dual Inline Packages or DIPs Referring to Figure 4 10 identify the
145. ear the on off switch S1 Expected 1 6 Vrms Actual LF Amp Noise Gain RF sheet 2 l ee gt gt Turn the signal generator off and disconnect it from the antenna jack Connect a 50 ohm dummy load Turn off all nearby equipment especially computers or signal sources Set AF GAIN to maximum Set RF GAIN to minimum Make sure the preamp and attenuator are both OFF Verify that FL1 is selected bandwidth 1 50 as well as CW Normal mode AF Output Min IF gain Setup the DMM for its lowest AC volts range Measure the signal at the speaker jack 5 near the on off switch S1 Expected 0 000 0 001 Vrms Actual AF Output Max IF gain Set RF GAIN to maximum Measure the signal at P5 pin 1 Expected 0 007 0 013 Vrms Actual Preamp Noise Gain Turn the preamp Measure the signal at 5 Expected 0 030 0 060 Vrms Actual I Noise Increase w Antenna Connect an antenna The signal at PS should increase substantially even if atmospheric conditions are quiet A typical reading on 30 or 40 m is 0 20 0 40 Vrms In general the longer or higher your antenna 1s the greater the noise increase will be 12 Final Steps If you have completed receiver signal tracing and any necessary repairs you should then do the following 1 Re install the bottom cover and heat sink Re do calibration of the VCO BFO band pass filters crystal filters etc as needed see RF Board Alignment and Test parts I II and II
146. elay Do not bend or trim relay leads Turn the board back over and verify that all of the relays are in the correct orientation and are seated flat on the board Solder all of remaining relay pins 35 Install R1 and R2 220 ohms RED RED BRN near the back left corner of the board AN To avoid stray signal coupling all capacitors on the RF board must be mounted as close to the PC board as possible without damaging the leads or their epoxy coating Install and C2 001 uF 102 which are on the left edge Install electrolytic capacitors C105 and C106 2 2 uF located near the front left corner LJ Install R35 and R36 82 GRY RED BLK just to the right of C105 Install R115 05 ohms 3 watts at the front right corner of the board Form the leads as indicated by the component outline Install the following components to the left of R115 __ C111 2 2 uF electrolytic R113 82 GRY RED BLK lead goes into the square pad LJ Install the internal speaker connector P5 which is a 2 pin connector like that shown in Figure 4 5 P5 is mounted near the on off switch S1 Position the connector as shown by its component outline with the vertical locking ramp toward 51 Install high current diodes 210 and D12 large black body located near the right edge of the board __ 010 9550015 __ 012 SB530 1N5821 may be substituted for D12 LJ Install the fol
147. en you install the panel mount potentiometers in the next two steps do not push on the shafts which may damage the part Push only on the metal frame 25 Install the audio taper potentiometer R3 in lower left hand corner The PCB is labeled AUDIO at R3 Push only on the frame not the shaft Make sure that the potentiometer body is parallel to the PC board and 1 pressed against the board as far as it will go before soldering C Install the four 5 k linear taper potentiometers at R1 R2 R4 and R5 The PC board is labeled LINEAR at each pot Verify correct positioning as you did in the previous step AN Before installing J1 in the following step review Figure 3 3 page 8 to be sure you have J1 on the correct side of the board The front panel attaches to the RF board via 11 a 20 pin single row female connector Install on the bottom side of the board Figure 5 7 Solder just two pins one at either end Bottom side of PC Board 4 Figure 5 7 Re heat the two end pins and press the connector down until J1 is seated flat against the board then solder the remaining pins 26 Install rectangular gray key caps on S1 and S3 so the key caps are parallel to the long axis of the PC board Figure 5 8 The caps are installed simply by pressing them onto the switch plungers Gray keycaps Square Keycap Figure 5 8 L Install a square black key cap on 57 as shown above Inst
148. entation of the polarizing nub before soldering ELECRAFT Polarizing nub Figure 5 4 Install two 3 16 4 8 mm diameter x 1 4 6 4 mm long round standoffs on the top of the board adjacent to the microphone jack Figure 5 5 Use two 4 lock washers between each standoff and the PC board as shown Secure the standoffs from the bottom side with chassis screws Recall that chassis screw is short hand for 3 16 4 8 mm long pan head machine screws Figure 5 5 ELECRAFT Install another 3 16 4 8 mm diameter x 1 4 6 4 mm long round standoff on the top of the PC board on the left side of the large square hole in the middle of the board The standoff mounting hole is below C2 Use the same hardware as indicated Figure 5 5 including two 4 lock washers and one chassis screw Install two 1 4 6 4 mm diameter x 1 2 12 7 mm long hex standoffs on the bottom of the board Figure 5 6 The holes for these standoffs are indicated by large pads on the top and bottom of the board Use one lock washer and a chassis screw for each standoff Insert the lock washer between the standoff and PC board Bottom of PCB Figure 5 6 Identify the two different types of panel mount potentiometers Four of them are 5 kohm inear taper types labeled B5K The fifth is an audio taper type labeled ASK They may be physically identical or have slightly different shafts body colors etc AN Wh
149. er components on either side of the PC board ae 12 RFC4 10uH Ww 119 126 01 A7uF I 45 C133 C135 47 O 1 01 21 IL 5 T2 680 10uH 12 8 FT37 43 2SC1969 2 115 C122 01 56 Sh 3 UE 1 R58 180 C121 C120 TEN 2 1 01 01 R49 RFC6 116 8T 33 120 0 68 MEE T1 2SC1969 9 3 FT37 43 wee R44 Q6 680 2 7K VN 2SC2166 R40 C118 Cr 48 R47 22 470 01 120 47 R50 1 52 NOTE WIND 4 2 2 1 1 FOR 7 HONI 0 1 Power Amplifier PA Q5 BETTER EFFICIENCY AT 5W PRE DRIVER 5 Sh 3 2N5109 E v SEE MODIFICATIONS SECTION C125 22uF L pe Driver R41 560 S C117 Q10 Z 8T 0 047 2N7000 D 8T 270 120 Pre Driver Q13 V BIAS XFIL PN2222A Q11 PN2222A C137 L 100uF C138 047 L R60 100 CLASS R63 Elecraft K2 RF Board 220 R62 By W Burdick Rev Date Sht 2 7K E Swartz F 1 27 04 4of4 Appendix B see T R 5 BAND _ PASS T R Lu FILTERS Ursus sa LOW PASS FILTERS POST RCV MIXER _ NOISE E CRYSTAL MIXER AMP BLANKER FILTERS PLL VCO MCU AND SYNTH 6 24MHz SUPPORT BFO AUDIO CIRCUITS 4 915MHz FILTER AF AMP Shaft Encoder pr EBENEN DISPLAY Y SEN AND CONTROLS Common Transmit Receive Appendix BLOCK DIAGRAM W Burdick E Swartz Rev D 1 9 04 Appendix Troubleshooting If
150. es Check the AuxBus signal at the MCU pin 40 CTRL U6 If you don t see this voltage drop below 5V briefly when the band is changed the MCU may not be functioning 075 If you saw the message INFO 090 or INFO 091 onthe LCD one of the EEPROM write tests has failed Check all voltages on the EEPROM CTRL U7 Remove the control board and inspect U7 and surrounding traces Verify that U7 is properly soldered Receiver 100 149 Problem 100 Low audio output from receiver or general receiver gain problem 110 AF amp not working Troubleshooting Steps If you hear audio output on some bands but not all of them check the band pass and low pass filters and T R switch 120 Make sure you have headphones or speaker connected and AF GAIN not at minimum Check for missing audio filter option KDSP2 or KAF2 or their bypass jumpers Check the key jack for a short to ground Make sure RF GAIN is at maximum The AGC threshold control R1 Control board may be set incorrectly Typical voltage at U2 pin 5 is 3 90 volts no antenna RF GAIN at max You can set for a slightly higher voltage at U5 pin 5 to increase the no signal gain If R1 is adjusted you ll need to re adjust CAL S HI and CAL S LO S meter If you have the 160 m RXANT option board installed you may have menu entry RANT turned ON but no receive antenna connected this may affect only one band since RANT can be set individua
151. es double sided Boards of this type require plated through holes to complete electrical connections between the two sides ELECRAFT When you solder components on these boards the solder fills the plated holes making excellent contact This means that you do not need to leave a large fillet or build up of solder on top of the pads themselves small amount of solder will do for all connections Unfortunately removing components from double sided PC boards can be difficult since you must get all of the solder back out of the hole before a lead can be removed To do this you ll need solder wick and a vacuum desoldering tool see techniques below The best strategy for avoiding de soldering is to place all components properly the first time Double check values and orientations and avoid damaging parts via ESD When removing components Don t pull a lead or pin out of a hole unless the solder has been removed or you are applying heat Otherwise you can literally pull out the plating on the plated through hole Limit soldering iron contact to a few seconds at a time Use small size solder wick about 0 1 or 2 5 mm wide Use wick on both the top and bottom pads when possible This helps get all of the solder out of the hole Buy and learn how to use a large hand operated vacuum desoldering tool such as the Soldapullt model DSOI7LS Small solder suckers are not effective With ICs and connectors clip
152. esistor TAN Color 50097 R14 Rubber bumper 040 or 047 thick RB1 RB2 x 312 square For top corners of FP PCB 5 2 1200 770101121 SIP 10 resistor pack ALT 10411216 E510012 1 RP1 100K SIP 10A1 104G SIP 10pin resistor pack ALT 770101104 E510010 1 R10 R12 Lal l oa N x 2 Q 5 D e 5 3 D NO NO N N m cO Co N Page 2 Front Panel Appendix K2 Front Panel Board Parts List p n E850003 PICTURE Designators Value Description Part Number QTY 51 52 53 54 55 56 57 S8 59 510 511 512 513 514 515 516 switch push button Front Panel push button switches E640005 16 Misc 140 pin socket for LCD driver chip U1 E620017 1 MEM PCF8566PN LCD Driver chip 40 pin E600027 1 U1 8 bit parallel in serial out shift register 16 U2 74HC165N pin E600028 1 TPIC6B595N 8 bit serial in parallel out shift register 20 U3 U4 Alt 6B595KA pin E600032 2 Z1 100 count incremental encoder w straight Shaft Encoder pins VFO main tuning control E640003 1 PCB2 front panel Printed Circuit Board Front Panel E100083 1 3 Front Panel Appendix PICTURE K2 RF Board Parts List p n E850001A and E850001B Designators Value Description Part Number QTY C1 C2 C9 C17 C26 C27 C37 C38 C39 C49 C57 C64 C77 C79 C80 C81 C82 C89 C91 C100 C140 C167
153. et using ST L page 96 Crystal Filter Selection Each operating mode provides up to four filter settings FLI FL4 Bandwidth and BFO settings be customized using CAL FIL page 88 Tapping cycles through the filters FL2 3 or 4 can also be turned OFF Filters and Operating Modes The CW Normal and CW Reverse crystal filter selections are tied together For example if you switch to FL2 when in CW Normal mode CW Reverse also switches to FL2 The same applies to the LSB and USB modes Checking Filter Status You can check the current filter number and its bandwidth without changing filters by holding For example you might see FL2 0 80c If a KAF2 or KDSP2 audio filter 1s installed and enabled you ll see audio filter info after the crystal filter display e g AF1 CF1 SF1 Bandwidth settings below 0 20 may cause excessive signal attenuation ELECRAFT Audio Filter Control If you have a KAF2 or KDSP2 option audio filter and real time clock installed will control audio filter selection Tap DISPLAY to activate other features Preamp The preamp provides about 14 dB gain If you experience strong in band interference you may want to turn the preamp off Attenuator If necessary 10 dB of attenuation can be switched in by turning on the attenuator This is more effective than using the RF GAIN control in the case of strong signal overload Scanning See Advan
154. ew holes were recently added to the lower rear panel to provide more convenient low level transverter I O Refer to the K60XV manual 84 Controls and Display LCD and Bargraph Meter The LCD shows the operating frequency and other information depending on selected display mode The LED bargraph functions as an S meter on receive and RF out or ALC meter on transmit Power Up Messages The LCD will display ELECRAFT for two seconds on power up If a problem is detected the display will show INFO 100 or a similar message The number shown corresponds to a paragraph in the Troubleshooting section Mode Indicator A letter at the right end of the display tells you the operating mode C CW L LSB or U USB A fourth mode RTTY data can also be enabled and uses the letter r page 104 If a small bar appears above the it means that the CW sideband is inverted CW reverse or DATA reverse The mode indicator will also flash slowly in two cases CW TEST mode see page 96 and SPEECH VOX mode see page 98 Annunciators The LCD provides eight Chevron shaped annunciators or status indicators NB noise blanker on flashes if Low Threshold setting is selected using ANT2 ant 2 selected requires ATU PRE pre amp on approx 14 dB ATTN attenuator in 10 dB A VFO A selected flashes in SPLIT mode B VFO B selected flashes in SPLIT mode RIT RIT turned on flashes if wide range selected XIT XIT turned on flas
155. f the board ELECRAFT Figure 4 3 A The voltage regulators U4 and US will be installed in the following steps These regulators have different voltages and must not be interchanged Check the labels before soldering Install U4 LM2930T 8 05 78 05 7805 1 7805 etc forming the leads as indicated Figure 4 4 Fold the pins over the shaft of a small screwdriver to create smooth bends After inserting the leads into the proper holes secure each IC with a 4 40 x 3 8 9 5 mm machine screw 4 lock washer and 4 40 nut These regulators may have either plastic or metal mounting tabs Use smooth E bend not sharp LH uU Figure 4 4 L Solder the voltage regulator ICs L Trim the IC leads as close to the PC board as possible ELECRAFT Install 40 pin IC socket at U6 The microcontroller will inserted into the socket in a later step Orient the notched end of the socket to the left as shown on the PC board outline Bend two of the socket s diagonal corner leads slightly to hold the socket in place then solder only these two pins If the socket does not appear to be seated flat on the PC board reheat the solder joints one at a time while pressing on the socket Solder the remaining pins of the 40 pin socket The connectors used in the following steps have plastic bodies that can may melt if too much heat is applied during soldering causing the pins to be mis positioned Limi
156. fly turn on RIT It s OK to have both and on at the same time In this case the OFFSET control can be thought of as an extension to the main tuning knob but covering only a small frequency range As with if you have or XIT enabled the transmit frequency will be displayed when you transmit and the receive frequency will be restored a minimum of 1 2 second later FINE RIT In some cases you may want to control the VFO in smaller steps to fine tune signals on receive This can be done using the FINE RIT feature described on page 102 We did not include detent on the offset knob because experience has shown that knob detent mechanisms degrade over time making it difficult to adjust the offset near the zero point However you can always return the offset knob to the zero point by simply matching the RIT on and RIT off frequency displays or by turning RIT off ELECRAFT Automatic Antenna Tuner ATU Both the low power internal automatic antenna tuner model and high power external antenna tuner 100 can match nearly any coax fed or random length antenna on multiple bands ATU functions will be covered briefly here refer to the specific ATU manual for details The operating mode of the KAT2 or KAT100 is selected using the ATU menu entry and is normally set to AUTO The menu entry also allows you to see the L and C selection step through ATU relays etc Note If y
157. for DOT mode using the GRPH menu entry Set power output to 5 0 W using the POWER control Tap DISPLAY to enter voltage current display mode When this display is selected you can use to check your voltage and current in transmit mode Enter tune mode and note the change in voltage and current Current drain at 5 watts is typically 1 3 to 1 6 amps If the current reading is much higher than this or if the voltage drops more than 1 V you may have a problem in the transmitter load or power supply see Troubleshooting Return to frequency display using DISPLAY switch LJ Set the POWER control for 10 0 watts Enter tune mode just long enough to verify that the wattmeter reads approximately 10 watts If you then switch to voltage current display and hold again you should see a current drain of typically 1 8 to 2 amps If you see a HI CUR warning message high current use CAL CUR to set your transmit current limit higher If current is much higher than 2 A see Troubleshooting This completes transmitter alignment and test on 40 meters 9 The K2 transmitter is most efficient at 10 watts and higher current drain at 5 watts CW may be higher than expected This is unavoidable because the K2 is capable of up to 15 W output Also for a given power level SSB transmission requires more transmitter overhead to prevent distortion 76 Receiver Pre Alignment Since the same filter
158. h the KAF2 and KDSP2 audio filter options You should not install J1 and J2 or an audio filter option until after K2 assembly and checkout have been completed Install short wire jumpers at R18 and R19 Make the jumpers from discarded component leads as you did above but keep them flat against the board Solder the jumpers on the top side Install the following resistors on the bottom side of board solder on the top side R12 820 GRY RED BRN __ R11 47 YEL VIO ORG 18 AN The connectors along the bottom edge of the board P2 and P3 will be installed next It is very difficult to remove them once they are soldered Follow all instructions carefully Hold the Control board vertically as shown in the side view below Figure 4 7 The top side of the board the side with most of the components should be to the right Turn to page 8 and review Figure 3 3 which shows how Control board plugs into the RF board P1 P2 and P3 will all be installed on the top side of the Control board as shown Position 6 pin right angle connector as shown in the side view below Figure 4 7 Do not solder P1 until the next step The plastic part of the connector must be seated flat against the PC board and the pins must be parallel to the board Do not bend or trim the pins on the bottom of the board Top side of m PC Board Figure 4 7 Solder just the two end pins of P1 then examin
159. he RF board via connectors P1 P2 and P3 along the bottom edge of the schematic P1 handles the AGC signals while P2 provide miscellaneous I O Redundant connections are provided for ground supply voltages low impedance signals such as audio output and a few other critical signals U6 is a PIC18C452 microcontroller MCU with 8 of EPROM 300 bytes RAM serial I O parallel I O and A to D inputs It is self contained with the exception of its 4 MHz crystal oscillator X2 Even when running at 4 MHz the PIC processor is very efficient it only draws few milliamps at 5 V Also since the program and data memories are located on chip there is very little noise radiation from the MCU 109 To get the most out of the available I O on the MCU much of the communication from MCU to the rest of the K2 is done via serial interfaces RS232 Used for communicating with a computer via P4 Aux I O 12 Display driver data SPI The serial peripheral interface 15 used to access various peripherals including the PLL and DACs AuxBus 1 data network for co processor control Shift registers serial to parallel shift registers are used to access MOSFET LED drivers on the front panel a parallel to serial shift register on the front panel 1s used for reading pushbuttons In addition to the microcontroller the Control board provides a number of specialized hardware interfaces Circuitry 1s described moving from left to
160. he heat sink 1s removed and re installed If a short 15 measured remove the heat sink and investigate the cause The most likely reason for a short is mis alignment of a shoulder washer or thermal pad thermal pad or shoulder washer is damaged it must be replaced There are four more 4 holes in the heat sink two on the bottom and two on the back panel Use four chassis screws to secure the heat sink to the side panels and RF board at these locations You may need to adjust the positions of the 2 D fasteners on the side panels slightly Install the washers and finishing nuts that you removed earlier from the antenna and key jacks The antenna jack hardware is shown installed in Figure 6 34 74 Alignment and Test Part In this section you ll complete alignment and test of the K2 on all bands Make sure the power switch S1 is in the OFF position out Connect your power supply or battery For transmitter tests a battery or well regulated power supply that can handle at least 2 amps 1s recommended Avoid using a switching power supply unless it is well shielded and includes EMI filtering A linear mode supply will typically generate much less noise in the HF bands See any recent ARRL Handbook for examples of both types Connect a 50 ohm dummy load such as the Elecraft DL1 to the antenna jack The dummy load should be rated at 10 watts or higher The DLI is rated at 20 watts Connect p
161. he leads slightly to hold it in place while soldering ELECRAFT Install the 1N4148 diodes listed below D1 is in upper left hand corner of the PC board If a diode has only one band the end with the band the cathode should be oriented toward the banded end of the corresponding PC board outline If a diode has multiple bands the widest band indicates the cathode end __ DI 1N4148 __ D2 1N4148 L Double check the orientation of the diodes then solder Find the component outline for diode D3 near the top edge of the board right end Install and solder resistor R22 at this location 82 k gray red orange Install the small fixed capacitors listed below beginning with C2 the upper left hand corner of the board This list includes all of the fixed capacitors on the Control board except the tall cylindrical electrolytic types which will be installed later The list shows both the value and the capacitor labels using notation explained in the previous section After installing each capacitor bend the leads outward to hold it in place but do not solder Note Remember to complete all items in each line before moving on to the next Install C2 C3 and C4 then C7 etc 2 001 102 gt __ 3 01 103 C4 047 474 C7 330 331 C6 047 473 C8 39 39 7 C9 01 103 C10 01 103 C12 0027 272 C5 01 103 C14 047 473 _ C17 01 103 042
162. he rubber stem bumper directly on top of L33 s component outline Flush trim the leads of all parts under or near L33 so the stem bumper can sit flat on the PC board Locate the pre wound BFO inductor L33 41 uH 5 It may be supplied in a small envelope or bag labeled L33 Press L33 down onto the stem bumper as far as it will go Position L33 and the stem bumper as shown in Figure 6 20 Locate resistor R116 1 8th watt 5 1 megohm green brown green Bend the leads of R116 down at 90 degree angles to match the spacing of L33 s pads Figure 6 20 Insert R116 s leads into L33 s pads then press the resistor down directly on top of L33 The resistor s body should be partially recessed into the well left in the center of the toroid Use the leads of R116 to hold L33 firmly to the board Figure 6 21 bending them outward on the top side Solder R116 Solder L33 s leads to the leads of the resistor points as shown in Figure 6 22 Keep L33 s leads as short as possible and away from any nearby component pads Trim off the excess portion of L33 s leads Note Trimming fine wire may be difficult with worn or poor quality diagonal cutters Be careful not to stress L33 s leads in the process Use a magnifying glass if necessary ELECRAFT R116 L33 Stem Bumper Figure 6 22 L To ensure that R116 cannot short to the bottom cover attach a thin self adhesive insulator to the bottom co
163. he screw should be inserted from the bottom side of the RF board the washer and nut go on the top Verify that body of Q6 is not touching leads of any adjacent components then solder Wind and install each of the low pass filter inductors listed below starting at the back right with L16 and L17 80 meters Wind each of the toroids using the core type and number of turns indicated use red enamel wire Review the toroid winding instructions and illustrations for RFC14 Page 53 __ L16 T44 2 red 21 turns 19 48 cm dl T44 2 red 21 turns 19 48 _ LIS T44 2 red 9 turns 10 25 em 19 T44 2 red 8 turns 9 23 _ 120 T44 2 red 7 turns 8 18 Note The black cores below are all of the powdered iron ceramic type not ferrite If necessary you can identify them by measuring their diameter which is 0 44 11 mm not 3 8 9 5 mm E21 T44 10 black 9 turns 10 25 cm 122 T44 10 black 8 turns 9 23 cm 123 T44 10 black 11 turns 11 28 cm __ 124 T44 10 black 10 turns 10 25 cm 67 AN It is very important to wind and install toroidal transformers T1 through T4 exactly as described in the following steps Remember that transformer windings are identified by numbered pairs of leads which correspond to the PC board and schematic TI is wound on an FT37 43 ferrite core dark gray and has windings similar to those shown in Figure 6 25 The 1 2 winding
164. hes if wide range selected Decimal Points The decimal point to the right of the 1 kHz digit will flash slowly if the VFO is locked by holding See Advanced Operating Features for other cases where decimal points flash scanning page 99 AGC OFF page 100 ELECRAFT SPLIT RIT XIT LED Optional You can install an LED on the front panel that will turn on whenever SPLIT RIT or XIT is in effect See the associated application note Adding a SPLIT RIT XIT LED to the K2 Potentiometers receiver audio level AF GAIN RF GAIN receiver RF level Turning this control CCW counter clockwise decreases receiver RF sensitivity At the same time it increases the bargraph S meter indication to remind you that you re not at full receive sensitivity The farther CCW the control is set the stronger a signal must be before it results in a meter deflection KEYER keyer speed control When you turn this control keyer speed in words per minute WPM will be displayed e g SPD 18 The speed can be set from about 9 to 50 WPM POWER power output control When you turn this control power output will be displayed in watts e g P 5 0 The range is 0 1 to 15 W for the basic K2 and 1 to 100 W if you have the KPA100 amplifier installed See Basic K2 Operation for details on controlling power output page 93 OFFSET RIT XIT offset This control provides a default range of 0 6 kHz in 10 Hz steps when RIT and or are enable
165. illator range error Troubleshooting Steps INFO 201 isan informational message only not a problem indication You will see INFO 201 one time on power up The only other time you might see this message is if you install a new version of the firmware that requires a reformat of EEPROM In most cases new firmware should not cause an EEPROM reformat however INFO 230 is displayed if you try to use CAL FIL without the frequency counter connected to the BFO test point RF TP2 INFO 231 is displayed if you try to use CAL PLL without the frequency counter connected to VCO test point RF TP1 INFO 232 is most likely to be displayed if you use CAL PLL without first selecting 40 meters INFO 235 is displayed if CAL PLL cannot complete VFO linearization due to inadequate PLL reference oscillator range RF Q19 You may have the frequency counter probe on the wrong test point should be on TP1 Re test the PLL reference oscillator using the procedure described under PLL Reference Oscillator Test in Part II of the RF board Alignment and Test section If the PLL reference oscillator range is found to be inadequate X1 may be defective Also check D16 D17 C84 C85 and L31 for proper value Signal Tracing Signal tracing is the primary method by which radio equipment is tested and repaired You can solve nearly all receiver and transmitter problems yourself by following the steps in this section carefully RF Probe Assembly Your
166. installed and enabled the range 15 0 1 to 110 watts with the amplifier module disabled at 10 watts or lower In CW mode you must send a few CW characters or press TUNE to allow the ALC automatic level control to lock in the new power level Requested vs Actual Power The POWER control sets the requested power which may exceed the actual power that the transmitter can achieve To see actual power output use see below In tune mode the display always shows the actual power output except when the display 1s showing voltage and current or when the ATU 1s doing an autotune The power displayed will be accurate to within about 10 if the load at the antenna is matched 50 ohms Using Hold to key the transmitter You ll hear one beep when you start tune and another when you terminate tune by tapping any switch or hitting the keyer paddle ATU If you re using KAT100 automatic antenna tuner pressing will drop power to either 2 or 20 watts maximum depending on whether the 100 is in use and may trigger a re tune of the antenna matching network You can also override power reduction by holding DISPLAY see page 94 Transverter Bands Maximum power output on each transverter band can be set in watts or milliwatts the latter requires the K60XV option See page 105 Current Limiting To protect the transmitter and power supply battery from excess current drain you can program a trans
167. ipment that uses a large AC power transformer This could result in modulation of the K2 s low level signal sources 83 Antenna A well matched antenna 50 2 or an antenna tuner should be used with the K2 Some high SWR conditions may result excessive current drain unless power is reduced If you have the KAT2 antenna tuner option installed the K2 s power control and power output display will be much more accurate under all SWR conditions Keying Devices Any type of hand key bug or external keyer can be plugged into the KEY jack or you can use the K2 s built in memory keyer In all cases you must use a stereo plug with the keying device a suitable plug 15 provided with the kit Also see CW Operation page 95 Microphone A standard 8 pin microphone jack is provided on the front panel A jumper block on the front panel PCB is used to configure the mic jack for specific microphones Refer to the SSB adapter manual Headphones Any type of mono or stereo headphones at nearly any impedance will work with the K2 However for best results we recommend high quality stereo headphones with full ear covers and 1 8 3 mm plug External Speaker The K2 has a built in high sensitivity 4 ohm speaker You can also plug in an external 4 or 8 ohm speaker at the EXT SPKR jack Option Connectors A number of mounting holes are provided on the back panel of the K2 for specific option connectors See Options page 113 Two n
168. isplay for 40 meters 7100 00c The letter C indicates CW mode The annunciator for VFO A will also be turned on If you see any other INFO messages or the display does not come on refer to Troubleshooting ELECRAFT L Turn the K2 off and wait for a few seconds then turn it back on The display should now show ELECRAFT for about two seconds followed by the frequency display Now that the EEPROM is initialized this 1s the display you should always see on power up The and T in ELECRAFT appear in lower case letters due to the limitations of the seven segment LCD characters Tap the DISPLAY switch once to select voltage current display The display should now show something similar to this E12 0 10 08 This would indicate that the power supply voltage E 1s about 12 0 V and the supply current I is about 80 100 mA Optical Encoder Test Tap the DISPLAY switch to return to the frequency display Turn VFO knob in both directions and verify that displayed frequency changes accordingly Tap the RATE switch to the right of the knob to change the tuning rate and repeat the VFO test at each rate Relay Test Tap IBAND After a short delay the K2 will switch to the next band At the same time you ll hear one or more relays Tap the switch 7 more times to verify that you hear relays being switched with each band change Note The
169. just the band pass filters An analog wattmeter or oscilloscope is ideal However in the instructions that follow we ll assume that you re using the K2 s built in digital wattmeter which will also provide satisfactory results LJ Set the POWER control for 2 0 watts L Switch to the 40 meter band and set the VFO for about 7100 kHz Locate 40 meter band pass filter inductors L1 and L2 and be prepared to adjust them using the wide end of the tuning tool AN In the following steps you ll place the K2 into TUNE mode by holding You should limit key down periods to about 5 or 10 seconds during tune up for safety reasons If you see or smell smoke turn the K2 off and refer to Troubleshooting Note While in tune mode it is normal to see power drift upward several tenths of a watt You may also see a sudden jump in power during alignment The output will quickly be reduced to about 2 0 W by the firmware 1f this happens Put K2 into tune mode and activate built in wattmeter by holding Using the alignment tool adjust L1 for maximum output Tap any switch to exit TUNE mode Enter tune mode again and adjust L2 for maximum output Tap any switch to exit 79 If necessary repeat adjustment of L1 and L2 two or three times to be sure that you have the inductors peaked correctly If you cannot get power output to 2 0 watts or higher see Troubleshooting Make sure the bar graph is set
170. ket as it will go and that none of its pins are bent Note The revision label on UI may not be oriented in the same direction as the text printed on the IC Use only the notch or dimple to identify the pin 1 end Visual Inspection Examine the RF board carefully for unsoldered pins solder bridges or cold solder joints Set switch 51 on the RF board to the OFF position Plunger OUT is OFF plunger IN is ON Resistance Checks Perform the following resistance checks Res to GND R115 right end near 51 12V IN gt 500 ohms Ul pin 1 gt 500 ohms Ulpinl K13 control 38 AN When working with the side panels in the following steps place a soft cloth on your work surface to protect the paint Locate two side panels Remove any masking tape from the panels using the same technique described in the Front Panel section taking care not to scratch the outer surfaces Arrange two panels shown in Figure 6 6 and verify that they are mirror images of each other The 2 D fasteners to be attached in the next step go on the inside surface which has bare aluminum areas that were masked during painting Note the actual size and shape of masked areas may vary Left Side Panel inside surface Right Side Panel inside surface Figure 6 6 ELECRAFT Holes offset away from panel Figure 6 7 Install two 2 D fasteners on each side panel at the locations indicated b
171. l problems with kits are due to incorrectly installed components or poor solder joints You can avoid these problems by doing a simple visual inspection A few minutes spent here may save you hours of troubleshooting time Make sure there are no components installed backwards Check all diodes resistor networks electrolytic capacitors and ICs The parts placement drawings in Appendix F will be helpful when checking diode orientation Examine the bottom of the PC board carefully for the following use a magnifying glass if available cold solder joints solder bridges unsoldered pins 21 Resistance Checks In the table below lt means less than and gt means greater than When measuring resistances that show a minimum value in the table such as gt 100 k your resistance reading may be much higher or even infinite This is typical when using a DMM digital multimeter If you use an analog meter you may find that some or all resistance measurements are too low Note Some digital multimeters will flash their display to indicate an infinite resistance Perform the resistance checks listed below to ensure that there are no shorts the most critical control circuits The Control board will be fully tested a later section 08 pin 16 gt 100 k 22 5 Front Panel Board The Front Panel board includes all of the control and display devices that you ll use when operating the K2 incl
172. l the tilt bail then second oval foot The bail should be compressed firmly between the two feet You may need to adjust the positions of the feet slightly before tightening the hardware Make sure the two feet are at exactly the same distance from the front edge of the bottom cover If they are not equally spaced the tilt stand may rock when in use C oo C C Figure 6 9 40 ELECRAFT Turn the RF board side panel assembly upside down Check for any untrimmed component leads on the bottom of the board Position the bottom cover as shown in Figure 6 10 then secure it using six chassis screws The heat sink and rear feet will not be installed until Part when the transmitter 15 assembled With the entire assembly still upside down or resting on one side panel plug the front panel assembly into the RF board Figure 6 10 Align the two assemblies so that connector J1 on the bottom of the front panel PC board mates with P1 on the bottom of the RF board The arrow in Figure 6 10 shows the approximate location of P1 on RF board Once front panel assembly is in place the headphone jack on the RF board should be just flush with the front panel The small rubber pads in the upper corners of the Front Panel board should be just touching the 2 D fasteners on the RF board If this 1s not the case the front panel must be pushed farther in Secure the front panel to the side panels and RF
173. latching relays are used to select one of eight VCO ranges thus requiring only a single high Q VCO inductor T5 The relays are optimally interconnected to allow for maximum coverage of the nine HF bands plus a large out of band tuning range Computer simulation was used to find a relay topology that allowed for the use of standard 5 fixed capacitors along with the smallest practical varactor diode capacitance As a result the VCO exhibits low noise on all bands and has a low max min tuning ratio on each band In order to provide some allowance for unit to unit variance in T5 a much higher value slug tuned inductor L30 15 placed across T5 s high impedance winding L30 has only a small effect on the Q of T5 but provides about a 20 tuning range The combined parallel inductance 1 very small only 1 uH resulting in a very large ratio on the lowest bands U3 buffers the VCO signal Q16 017 provide stable ALC to keep the VCO voltage fairly constant over the entire frequency range despite variations in the VCO transistor 18 Also shown on sheet 1 1 the DC input circuitry bottom right hand corner which is designed to protect the K2 and its power supply from almost any conceivable mis connection or short D10 protects the K2 from reverse polarity at the DC input while dropping only 0 1 0 2 volt F1 is a thermal self resetting fuse that goes into a high resistance state 1f a short or other high current situation exists anywhere i
174. ld look very similar to Figure 6 15 but with 10 turns rather than 14 Verify that the turns of RFCIA are not bunched together They should be evenly spaced and occupy about 85 of the core s circumference If the turns are all bunched together RFC14 s inductance value will not be correct Unless otherwise specified about 80 to 90 of the core should always be used Stripping Toroid Leads The enamel wire supplied with the kit can be heat stripped One way to do this is to place a small amount of solder a blob on the end of your soldering iron then insert the wire into the hot solder for a few seconds Another possibility is to burn the insulation off by heating it with a match or small butane lighter for a few seconds then use fine grain sandpaper to remove the enamel residue Avoid scraping insulation off with a razor blade as this may nick the wire Strip and tin the leads of the toroid before you mount it on the board As shown in Figure 6 15 you should remove the enamel from the leads up to about 1 8 3 mm from the core You should see only bare wire no insulation on the side to be soldered Install RFC14 vertically as shown by its component outline near the front left hand corner of the board then pull the leads taut on the bottom of the board Solder the leads of RFC14 When soldering make sure that the solder binds well to the leads If the lead appears to be an island in a small pool of solder
175. ld snap into place Each pin has a small tab on the back that latches into a hole in the housing when inserted Insert copper wire into the pin 1 position of a two pin housing as shown Insert the other wire into the pin 2 position Connect other end of this cable to external speaker jack as shown in Figure 7 4 The copper wire must be connected to the AF lug of the speaker jack Solder only the copper wire 79 Copper wire Figure 7 4 Connect one end of the 9 23 cm speaker cable to the speaker terminals The copper wire should be connected to the lug marked on the speaker Solder both wires Connect the other end of this cable to the external speaker jack as shown in Figure 7 5 The copper wire must be connected to the lug marked SP below Solder all three lugs SP Ground Copper wire Figure 7 5 Use three cable ties at the points shown in Figure 7 1 to hold the speaker cables in place Save the fourth cable tie for use with the supplied RF probe The ties should be pulled tight Trim any excess cable tie length 80 Finishing Touches Examine the Control board one last time to be sure that it is correctly plugged into the RF board three connectors must be mated completely Leave the frequency counter test cable connected to the BFO test point TP2 This will allow you to modify your filter and BFO settings 1f necessary during normal operatio
176. lengths of insulation from one end of wire These will be used to insulate the leads of C46 in the following steps Slip the two lengths of insulation over the leads of a 01 uf capacitor 103 This is a new component C46 not present on the board AN Figure 4 11 below shows the bottom side of the Control board Components shown with dotted outlines are located on the top side On the bottom side of the Control board solder C46 between R21 and the base lead of Q8 as shown below Keep lead length short C46 mE new Components shown in dashed lines K2 Control Board Bottom Foil Side are installed on the top of the board Figure 4 11 22 uF electrolytic capacitor has also been added C45 Solder C45 as indicated above between U8 pin 2 lead and U8 pin 14 lead Carefully compare your installation of C46 and C45 to Figure 4 11 Make sure the leads of these capacitors are soldered to the indicated pads Verify the orientation of the and leads on C45 ELECRAFT Option Components All component locations on the Control board should now be filled except for the following e 44 top side of the board near the microcontroller U6 This capacitor will not be used Jl and J2 bottom side These two connectors are provided for an audio filter option KAF2 or KDSP2 An audio filter should not be installed until the K2 has been completed and tested Visual Inspection Nearly al
177. let Gray White Silver Gold Multiplier x 1 x 10 x 100 x 1K x 10K x 100K x 1M Figure 3 4 ELECRAFT In addition to the tools supplied you will need these standard tools Fine tip soldering iron 20 40 watt temperature controlled preferred with 700 or 800 F tip 370 430 C C grade small diameter 031 solder DO NOT use acid core solder water soluble flux solder additional flux or solvents of any kind which will void your warranty Desoldering tools wick solder sucker etc Needle nose pliers Small point diagonal cutters preferably flush cutting Small Phillips screwdriver Jeweler s flat blade screwdriver While not required the following items are recommended DMM digital multimeter for doing resistance and voltage checks A DMM with capacitance measurement capability is strongly recommended see Identifying Capacitors Magnifying glass Conductive wrist strap Assembly Notes AN This symbol is used to alert you to important information about assembly alignment or operation of the K2 Photographs You should review the photographs in Appendix D to get an idea of what the completed PC board assemblies look like Step by Step Assembly Each step in the assembly process 1s accompanied by a check box 4 11 In some steps you will actually be installing multiple components of a particular type In this case the instructions will be followed by a table listing all of the
178. llowing steps you ll test the keyer audio tone generation only This tests the keyer jack speed control and potentiometer read circuits including the A to D converter on the microcontroller Tap MODE until C 1 displayed at the right end of the LCD indicating CW mode Plug paddle into key jack The plug must be stereo 2 circuit A mono plug will key the transmitter continuously A mating stereo plug for the keyer jack is supplied with the kit Using the menu s INP entry set up the keyer input for either or PDLr as described previously Adjust the KEYER control As soon as you turn it the display should show the keying speed approx 9 50 WPM While listening headphones test keyer paddle to verify that both dot and dash are working Note No sidetone will be generated when LSB or USB mode is selected L or U ELECRAFT Setting the AGC Threshold Make sure the RF GAIN control is rotated fully clockwise Locate potentiometer R1 on the Control board right side as viewed from the front of the K2 Set your DMM for DC volts Connect the lead of the DMM to one of the ground jumpers or to the K2 chassis ground Touch the lead to pin 5 of U2 on the Control board U2 1s located just above trimmer R1 Pin 5 is the pin nearest diode D1 Adjust R1 for a reading of 3 80 volts on the DMM This is the suggested setting but it can
179. lly about 12100 kHz Then tap and write down this frequency reading typically 12080 12090 kHz Ref High Freq Ref Low Freq Range kHz Subtract lower frequency reading from higher reading The range must be between 9 8 and 15 kHz if not see Troubleshooting Tap to exit CAL FCTR VCO Voltage Controlled Oscillator Test to select 80 meter band and set VFO for frequency of about 4000 10 kHz Connect the frequency counter probe to the VCO test point TP1 Activate the frequency counter using CAL FCTR as before You should now see a frequency counter reading in 8 to 10 MHz range It may or may not be stable at this time 1 the frequency may be changing If the reading 1s 0000 kHz or is changing rapidly you probably don t have the counter cable connected to the VCO test point If the reading 15 fairly stable but not between 8 and 10 MHz refer to Troubleshooting Tap MENU to exit CAL ELECRAFT VCO Alignment it completely from the K2 61 Table 6 1 VCO Voltage Readings In the following steps you ll adjust the VCO inductor L30 so that the VCO control voltage is in the proper range Band Low Freq Voltage High Freq Voltage 80m 3500 _ 4000 Disconnect the internal frequency counter probe and remove 40m 7000 7300 30m 10000 20 10150 20m 1400
180. lly for each band Peak the band pass filters 1f you have not already done so Check for ground shorts in the LPF and BPF by first resetting all of the relays 065 Turn the AF GAIN to maximum If you don t hear any hiss at the receiver output troubleshoot the AF amplifier 110 Check the 8V regulated supply voltage and troubleshoot if necessary 053 Measure the 8R line 8 receive at the anode of D6 on the RF board It should be 8V 0 5V If not look for a problem in the 8V switching circuitry control board Try using signal tracing see procedure later in this section 114 AGC or S meter not working 120 Signal loss only on some bands Use the menu to set a sidetone level of 60 ST L 060 Hold 2 If you hear a strong tone the amplifier itself 1 probably working check the mute circuit CTRL Q6 and Q7 and trace the volume control lines back to the product detector RF U11 Remove the control board and inspect the entire A F amplifier and mute circuit for mis installed components shorts and opens If AGC appears to be working but the S meter isn t try re calibrating the meter using CAL Hl and CAL S LO If the S meter 1 stuck you may have an open short or incorrect component in the area of U2 on the control board Make sure the RF gain control is at maximum If the AGC and S meter are both not working you may have a dead 5 068 MHz oscillator crystal X1 control board Listen for the 2
181. lower left hand corner 15 notched Open bag labeled MISCELLANEOUS and empty contents into a shallow box or pan This will prevent loss of any of the small hardware while allowing you to locate items as needed AN The Allen wrenches are located a small bag with the MISCELLANEOUS items These wrenches may have been oiled during manufacturing Remove the wrenches and wipe off the oil if any then discard the bag 13 AN There are five sizes of 4 40 machine screws provided with the kit The relative sizes of the screws are shown below for identification purposes not to scale of the screws are black anodized except for the 7 16 11 mm screws The 3 16 4 8 mm pan head screws are the most numerous and will be referred to as chassis screws throughout the manual There is only one flat head 3 16 screw Flat head 3 16 4 8 mm Pan head 3 16 4 8 mm chassis screws Pan head 3 8 9 5 mm Pan head 7 16 11 mm Pan head 1 2 12 7 mm Identify all of the 4 40 screws and sort them into groups 14 The side of the Control board with most of the components 1 the top side With the top side of the Control board facing you and the notch at the lower left locate the position of resistor R5 near the left edge The label R5 appears just below the resistor s outline Install a 33 k resistor orange orange orange at R5 with the ora
182. lowing components near D10 _ C77 001 102 __ C196 047 473 R69 100 BRN BLK YEL R66 2 7 RED VIO RED 36 LJ Install the self resetting fuse F1 near D10 1 is yellow and looks like a square bodied capacitor One side is labeled G300 Install key jack J1 at back left corner of board Before soldering make sure that the jack is aligned with its PC board outline Install the headphone jack J2 on the small board extension near the front left corner The pins on J2 are not very long so they will be nearly flush with the bottom of the board Solder the pin closest to the front edge first ground then verify that the jack 1 seated flat on its plastic nubs before soldering the remaining pins Install the power switch S1 at the right front corner SI s key cap will be installed later Install the DC input jack J3 at the back right corner The 3 leads on the jack must be lined up with the slot shaped holes in the component outline If the holes are a tight fit press firmly until the connector snaps into position Install the antenna jack 4 just to the left of J3 Install the following components near U1 at the middle of the board You may need to confirm the part number of U2 781 06 since it 15 easy to confuse it with U8 781 05 Use a magnifying glass if necessary U2 781 06 7 C140 001 102 2 C139 0 1 104 R64 100 B
183. ly used on 40 meters and below and USB is used on the higher bands Crystal Filter Selection If the SSB adapter is installed you ll be able to take advantage of its 7 pole fixed bandwidth filter designated OP1 in CAL FIL This filter can be used in all modes DSP Filtering Notch and Noise Reduction Refer to the KDSP2 option manual for details on these features SSB Menu Entries SSBA is used to set the mic audio level mic gain from 1 to 3 An additional setting BAL is used during SSB adapter alignment SSBC is used to set the speech compression level from 1 1 to 4 1 Higher settings add punch and are especially useful at low power levels PTT VOX Selection By default the K2 uses PTT push to talk via your mic s PTT switch To use VOX voice operated transmit hold the switch until you see SPCH 0 2 0 4 or 1 0 on the LCD The number 0 2 1 0 15 the VOX delay time in seconds Holding again restores the setting to PTT Power ALC Metering If you have the SSB adapter installed you ll be able to switch between RF and ALC bargraph meter modes by holding ALC metering is used only in SSB modes and may help in setting the mic gain and speech compression level The ALC reading starts from the right end of the bargraph rather than the left using BAR mode so you won t confuse it with the RF display Use RF meter mode except when checking ALC level ELECRAFT Microphone Configuration You ll need to configure
184. m this panel except that covering the RCV ANT and XVTR IN OUT holes Use a sharp tool to cut though the tape leaving a 1 2 12 mm border around these holes Then peel the tape off leaving these holes covered Attach two round rubber feet to the heat sink using 4 40 x 7 16 11 mm screws 4 lock washers and 4 40 nuts The screws are standard steel zinc plated not black anodized The nuts go on the inside surface of the heat sink The rubber feet can be found with the MISCELLANEOUS items Remove the finishing nuts and washers from the shafts of the antenna and key jacks They will be re installed later Turn K2 up on its left side This will keep transistor screws from slipping out during the following steps ELECRAFT Remove 4 40 nuts and 4 lock washers from mounting screws for Q7 and 8 but do not pull the screws out If you pull these screws out the associated hardware will fall off and will have to be re installed AN In the next step you ll install thermal insulation pads on the power amplifier transistors Q7 and Q8 These pads must be positioned correctly to keep the collectors of the transistors from shorting to ground Proper positioning 1s also required to guarantee good heat conduction Place self adhesive thermal pads top of Q7 and Q8 as shown in Figure 6 32 with the hole in the pad centered over the hole in the transistor tab The adhesive side must b
185. me manner as RFCIA Install RFC3 vertically just to the left of W1 Install 4 7 uH slug tuned shielded inductors marked T1005 at L1 and L2 near the back left edge of the board Install the 40 meter low pass filter components which are listed below These components are located near Q22 2N5109 transistor with heat sink __ C225 390 391 C226 680 681 C228 56 56 C229 220 221 __ C221 330 331 __ L25 T44 2 red 14 turns 26 red enamel wire 14 35 cm __L26 T44 2 red 12 turns 26 red enamel wire 13 33 cm AN The leads of some bottom mounted components may need to be pre trimmed before mounting and soldering See Page 11 Install following components bottom side of board starting with C207 at the back left Once all components have been installed solder them on the top side being careful not to damage any adjacent top mounted components C207 001 102 7 C224 047 473 C204 001 102 __ C216 001 102 __ C223 001 102 bend body down before soldering __ C208 001 102 __ 195 001 102 continued 57 __ C133 0 1 104 bend body down before soldering __ C135 01 103 C17 001 102 C29 12 12 C122 56 56 7 C27 001 102 7 C28 12 12 C119 01 103 C104 68 68 R34 2 7 RED VIO RED RFC2 100 uH BRN BLK BRN RFC7 15 uH BRN GRN BLK LJ Find the C6 label alo
186. mit current limit using CAL CUR see Calibration Functions 93 VFO Selection To select the or B VFO tap To set the unused VFO equal in frequency to the current VFO tap The currently selected VFO will determine both the transmit and receive frequencies unless you re running SPLIT see below A and B VFO frequencies are saved in EEPROM on a per band basis and are updated periodically see Backup Timer at the end of this section Split and Reverse Operation Split operation means transmitting and receiving on different frequencies This 15 useful for DX work since many DX stations will ask you to call them above or below their carrier frequency to avoid interference To enter split mode hold until the message SPLIT appears on the LCD Holding in again will display NOR normal The active VFO annunciator A or B will flash slowly when you re in SPLIT mode to remind you that this feature 1s enabled and that your receive and transmit frequencies are different Also each time you transmit when in SPLIT mode the transmit frequency is displayed for a minimum of 1 2 second When you re using split you can switch between your transmit and receive frequencies by tapping A B However there are times when you only want to quickly listen on your transmit frequency not switch VFOs In this case you can hold in the switch reverse which temporarily swaps the VFOs When you release REV the LCD will
187. n If there are any missing chassis screws in bottom cover heat sink side panels or front panel install them now Plug the internal speaker cable into P5 on the RF board just behind the on off switch S1 The connector is keyed and can only be plugged in one way AN Even if you have purchased some K2 options you should not assemble and install them yet The option manuals assume that you are familiar with basic K2 operation Remove the masking material from the two top cover mounting holes marked C in Figure 7 1 Cut through and peel off about 1 2 x 1 2 12 x 12 mm of masking material from around the top cover mounting holes marked D in Figure 7 1 These holes are in the far corners of the top cover s rear panel corresponding to screws J and 2 in Figure 7 6 Place the top cover onto the chassis and secure it using six chassis screws as shown in Figure 7 6 AN When removing the top cover in the future take out only the six screws shown in Figure 7 6 ELECRAFT LJ Attach the self adhesive serial number label to the rear panel of the heat sink in the space provided Write serial number on inside cover of your manual w Figure 7 6 This completes assembly of your K2 Please read the Operation section which follows and try each of the K2 s features AN If you did not have access to a frequency counter or calibrated receiver when aligning the 4 MHz oscillator you
188. n 20 pin male right angle connector the bottom of the board Figure 6 5 but do not solder P1 yet Review Figure 3 3 page 8 for correct placement The short ends of the bent pins are inserted into the holes and the long ends must be parallel with the board Top of board Front edge Pl Figure 6 5 Solder just two end pins of P1 Look closely at P1 to make sure that its plastic support is pressed down as far as it will go and that the pins are parallel to the board If not re heat the soldered ends while pressing it into place Once it 1s seated properly solder the remaining pins L To the left and right of the I O controller U1 you ll find two short jumpers labeled GND on the top side of the board Form 3 4 19 mm long U shaped ground jumpers and install them at these locations as you did on the control and Front Panel boards Use discarded component leads On the bottom of the board you ll find two additional ground jumpers one near the middle and the other near the back edge Install U shaped ground jumpers in these two locations 37 AN Before handling U1 touch an unpainted grounded metal surface or put on a conductive wrist strap Install the I O controller U1 PIC16F872 or 16F872A in its socket near the middle of the board Be sure to align the notched or dimpled end of U1 with the notched end of the socked to the left Make sure U1 is seated as far down in the soc
189. n a particular band or strange characters appearing on the LCD Before resetting the configuration to defaults try simply re entering the correct frequency and storing it in the affected memory If you find it necessary to reset to defaults record the following data first e filter and BFO settings for all modes filters using CAL FIL other CAL parameters e g S meter HI LO current limiting primary menu parameters secondary menu parameters if applicable To reset to defaults Turn the K2 off then hold down the M 8 and switches and turn power back on The EEPROM will be rewritten with factory defaults You can then re enter the data saved above using the menu functions Re doing CAL PLL is also recommended Computer Control of the K2 If you have the RS232 interface adapter installed model KIO2 or the 100 watt stage KPA100 you ll be able to use a computer to control the K2 Both the KIO2 and KPA100 provide true RS232 levels at 4800 baud with no need for a level converter The K2 s computer control capabilities are compatible with nearly all contesting logging and remote control software including Elecraft s k2remote and k2voice programs Control over the internet is also possible You can write your own programs as well see the KJO2 Programmer s Reference on our web site Refer to the KIO2 or KPA100 manuals for additional details ELECRAFT Fine RIT Mode The K2 s FINE RIT feature p
190. n that band For example if you try to switch to 8400 kHz which is typically outside the range of the synthesizer the K2 will switch to 40 meters and setup the VFOs as they last were on this band Tuning Rates The VFO tuning rate is selected by tapping RATE Default tuning rates include 10 Hz 50 Hz and 1 kHz per step resulting in 1 kHz 5 kHz and 100 kHz per VFO knob turn Other tuning rates can be selected see the RATES menu entry page 103 The frequency display changes to remind you of the current tuning rate At 10 Hz step two decimal places are shown 100 Hz and 10 Hz When you select 50 Hz step the 10 Hz digit 15 blank When you select 1 kHz step both decimal places are blank VFO Lock The current VFO frequency can be locked by holding the switch until LOC is displayed The decimal point will then flash slowly as a reminder Split Operation Lock applies only to the current receive VFO So while you are holding the REVI switch temporary VFO reverse you can change the frequency of the other VFO transmit overriding lock This is very useful when operating SPLIT since it allows you to check and modify your transmit frequency without unlocking the receive Holding the switch again cancels lock and displays NOR normal ELECRAFT Power Control Turn the POWER control to set the power output directly in watts e g P 5 0 The normal range of the control is 0 1 to 15 watts If you have the KPA100 option
191. nd E850001B PICTURE Designators Value Description Part Number QTY 51 Power Switch E640006 1 MISC Keycap TAC BLK Power Switch Keycap rectangular E980023 1 MISC 28 pin socket 0 3 Socket for U1 E620011 1 omall envelope contents listed on page 49 MISC PLL Upgrade parts of the manual E850146 1 heatsink TO5 Flush Crown heatsink for Q22 E700029 1 standoff 1 8 H x 1 4 D phenolic HW COLOR BROWN For PA Transistor Mounting 700034 2 HW stem bumper 0 5 dia black rubber For L33 BFO E980005 1 washer nylon 4 0 375 diameter For T5 700035 1 HW 4 32 nut nylon nut nylon For T5 00021 1 HW 4 32 screw nylon x 1 2 screw pan head nylon For T5 E 00022 1 Page 10 RF Appendix K2 Misc Bag Parts List p n 8 50004 PICTURE Designators Value Description Part Number QTY HW 4 lockwasher internal tooth E700010 41 2 56 screw 1 8 fillister head STAINLESS 2 56 x 1 8 slotted HW STAINLESS for LCD bezel E700023 4 2 D Fastener Chassis fasteners E100078 11 4 40 nut Steel ZN pan head Phillips screw black oxide steel incl 4 40 screw 3 8 black spares E700008 11 pan head Phillips screw black oxide steel incl 4 40 screw 3 16 gt E700015 56 4 40 screw 82 deg 3 16 flathead Phillips 82 deg 0 21 dia head Hd black black oxide steel front panel 700025 4 40 screw 1 2 black Phillips for mounting PA
192. nd the chassis pieces are designed to form a tight enclosure around it see photos in Appendix D In addition many option boards plug directly into the RF board to minimize wiring Assembly and testing of the RF board is broken into three parts Part I The DC and control circuits are installed so that the front panel and Control boards can be plugged in and tested The I O controller UI on the RF board is also installed and tested at this time Once this phase of assembly is completed you ll have the K2 s built in test equipment available for testing and aligning the remaining circuits Part II Synthesizer and receiver components are installed and tested By the end of Part II you ll have the K2 receiving on 40 meters Part III Transmitter components and all remaining filter components are installed The K2 is then aligned on all bands 33 Components AN Review anti static precautions before handling transistors or ICs Open the bags labeled RF and sort the components into related groups In later steps you ll sort some of the components according to value to reduce the likelihood of assembly errors Locate RF board and place it in front of you with component side up the side with most of the parts and the front edge facing you the edge with the irregular cutouts Throughout this section we ll refer to the different areas of the board in terms of their proximity to you For example front left
193. ne and 15 flush with the board before soldering Install the electrolytic capacitors in the order listed below starting with C60 near the far left hand edge Insert the lead of each capacitor into the hole with the symbol C60 100 uF __ C93 10 __ C103 220 uF 22 Looking at the bottom of RF board locate U4 MC145170 near C90 As shown by the X in Figure 6 14b the short trace from pin 16 of U4 to C89 on the top side has been cut at the factory ur d Pin16 X MC145170 bottom view C90 Figure 6 14b ELECRAFT C88 RFC15 100 C91 001 q o C90 Figure 6 14c Solder C91 001 uF 102 to two pads shown in Figure 6 14c Use short leads L Solder C88 68 pF 68 or 680 between pins 12 and 13 of UA as shown above Use short leads L Locate the miniature 100 uH RF choke RFCIS tan body brown black brown much smaller than the other 100 chokes in the kit RFC15 s leads are fragile do not pull on them LJ solder RFC15 to the pads indicated above Use short leads LJ Examine C88 C91 and 15 closely Their leads should not contact adjacent pads or traces ELECRAFT Locate the crystals used on the RF board 12 096 MHz 1 4 9152 MHz for BFO 2 and 4 9136 MHz for crystal filters 7 Do not mix the BFO and filter crystals which have different characteristics The bag of 7 filter crystals should have a number
194. ng the 2 D fasteners or there may be a small gap Figure 6 12 Push the black keycap onto S1 s plunger until it snaps into place Test S1 s action push on push off Leave the switch in the OFF position out 42 Alignment and Test Part 1 In this section you ll test most of the circuits on the Control board and front panel Along the way you ll become familiar with basic operation of the K2 including use of the front panel switches display and menu Before proceeding with initial test turn to first page of Operation section of the manual to familiarize yourself with the K2 s front panel layout Do not turn on power to the K2 at this time The Tap Hold Rule Each of the push button switches on the front panel has two functions one activated by a TAP short press and the other activated by a HOLD long press about 1 2 second The upper label on each switch shows the TAP function white lettering and the lower label shows the HOLD function yellow lettering To highlight this in the text we use two different typographical styles to identify switches and Initial Test AN If any test or alignment step fails refer to the Troubleshooting section Appendix E Set the controls on the front panel as follows AF GAIN midway 12 o clock RF GAIN maximum clockwise KEYER midway POWER minimum counter clockwise OFFSET midway ELECRAFT Locate P7 the C
195. ng the back edge The three pads near C6 are labeled J15 on the top side for use with the K60XV option Install C6 4 7 pF into the outer two of the three pads LJ Locate L31 a 12 uH shielded solenoidal inductor black case may not be color coded L31 15 mounted on the bottom of the board near the right edge Install group of components listed below the bottom of the board C183 is near the front left corner C183 01 103 CI61 01 103 C186 01 103 7 C150 330 331 __ C90 047 473 7 C157 047 473 bend body down before soldering bend body down before soldering __ R77 220 RED RED BRN R76 10 BRN BLK BLK 875 680 BLU GRY BRN R94 82 GRY RED BLK 99 270 RED VIO BRN _ R98 270 RED VIO BRN 100 820 GRY RED BRN __ R110 5 6 GRN BLU RED 4 3 9k ORG WHT RED 18 1 M BRN BLK GRN R29 10 BRN BLK ORG __ R19 2 7 RED VIO RED __ 12 100 uH BRN BLK BRN __ 036 5082 3081 fragile glass diode orient banded end as shown __ 1 mH BRN BLK RED 58 AN The BFO toroid L33 is supplied pre wound due to the large number of turns and very small gauge wire required When handling L33 be very careful not to damage the leads Locate the rubber stem bumper Clip off about one half of the tip of the stem using diagonal cutters L L33 is located on the bottom of the board near the front center Place t
196. nge 019 Leave D19 set to the default n no unless you have installed varactor diodes D19 and D20 in conjunction with the K60XV option 60 meters plus low level transverter I O At that time the parameter should be set to Y Note Do not install D19 and D20 until the K60XV option is installed K2 100 Mode Selection PA If you have the 100 option installed the PA menu entry shows the 100 watt stage s operating mode While editing the PA parameter tapping DISPLAY selects the fan mode nor LoHi Hi For more details refer to the KPA100 manual Appendix G of the K2 owner s manual which is supplied with the KPA100 kit ELECRAFT Transverter Bands TRNI TRN6 Six user definable bands are provided for use with transverters Once enabled individually using the TRN1 3 4 6 menu entries these bands will appear in the band rotation following 10 meters You can use Elecraft X V Series transverters and most other transverter types with the K2 Transverter switching Up to six Elecraft X V Series transverters can be controlled automatically using the K60XV option 60 meter adapter and low level transverter I O Refer to the K60XV manual for further details Transverter configuration These bands are set up using the T RN1 3 4 6 menu entries First tap MENU select the secondary menu SEC using DISPLAY and scroll to TRN1 2 or 3 Tapping 1 2 switches to TRN4 6 Next hold to highlight the first
197. nge bands at the top and the gold band indicating 5 tolerance at the bottom Make sure it is seated flush with the board then bend the leads on the bottom to hold it in place Do not solder this resistor until the remaining fixed resistors have been installed in the next step Install the remaining fixed resistors which are listed below in left to right PC board order The resistors should all be oriented with their first significant digit band toward the left or top This will make the color codes easier to read 1f you need to re check the values after installation Check 196 resistors with an ohmmeter Note When multiple items appear on one line in a component list such as the one below complete all items on one line before moving on to the next as indicated by the small arrow In other words install R5 first then R2 then go to the second line __ R5 33 k ORG ORG ORG R2 3 3 M ORG ORG GRN R3 I0k BRN BLK ORG R4 5 6 GRN BLU RED R6 100 BRN BLK BRN __ R7 1 78 1 BRN VIO GRY BRN R8 100 1 BRN BLK BLK BLK R9 806 196 GRY BLK BLU ORG 7 R10 196 196 BRN WHT BLU ORG J R16 10 BRN BLK BLK R17 3 3 M ORG ORG GRN R21 270k RED VIO YEL R20 2 7 ohms RED VIO GLD ELECRAFT LJ Solder all of the resistors then trim the leads as close as possible to the solder joints Some builders prefer to trim the leads before soldering Either method can be used Locate
198. nit still appears functionally dead 15 running slowly 005 No display but audio is OK Troubleshooting Steps Make sure your power supply or battery 15 connected turned on and isn t plugged in backwards Check power supply and battery fuses if applicable The K2 s internal self resetting fuse F1 may have gone into a high resistance state due to a short from the 12 V line to ground unplug the power supply and check for such shorts Examine power cable for shorts or opens Verify control board is plugged in and that its connectors are fully seated Check for 12 VDC at the power jack Make sure speaker battery and other internal option connectors are not swapped or plugged in backwards Measure the 5 and 8 regulated power supplies If either 1s incorrect check the regulators 050 Check the MCU 075 Check values of R16 and R15 on the front panel Check continuity from LCD driver U1 to LCD Also look for bent pins on driver Check the MCU Control U6 075 Verify that the control and front panel boards are plugged in correctly The MCU oscillator may be shorted out due to solder flux residue especially if you used water soluble flux solder 030 Remove the bottom cover and verify that the front panel connector is properly mated with the RF board If the front panel is plugged in correctly but the problem still persists check all LCD voltages and control lines 060 009 LO displayed 010 Battery voltage to
199. notched or dimpled end of the IC IC pins are counted starting from pin 1 as shown below and going counter clockwise Figure 4 10 Straighten leads of U2 see Figure 4 9 Install U2 in the orientation shown by its PC board outline near the upper left hand corner of the PC board but do not solder it yet Make sure the notched or dimpled end 1 lined up with the notched end of the PC board outline Even though the outline is covered when the IC 15 installed you can still verify that the IC 1s installed correctly by looking at pin 1 The PC board pad corresponding to pin 1 will be either oval or round AN You may overheat the IC pins or PC pads if you take an excessive length of time to solder After a few tries you should be able to solder an IC pin in about 1 or 2 seconds 19 Bend two of U2 s corner pins out slightly bottom of the board to hold the IC firmly in place flat against the top of the board Find pin 1 and verify that its pad is either round or oval Once U2 is properly seated solder all eight pins using a minimum of solder Install the ICs listed below Bend the pins to hold each IC in place as you did with U2 but do not solder until the next step The notched or dimpled end of each IC must be aligned with the notched end of its PC board outline Note For UI the IC type supplied may be either NE602 or SA602 J Ul NE602 U8 534 __ U3 LM6482 U9 LM380 U
200. nside the K2 F1 resets quickly once the source of the short is removed D12 provides reverse polarity protection for the internal battery 1f applicable 111 Sheet 2 Receiver and Low Level Transmitter Circuits The receiver is a single conversion superhet with an intermediate frequency of 4 915 MHz The preamp and attenuator are switched in using latching relays so that no current is required except when switching them on or off The mixer is a diode ring type providing good dynamic range Z6 and is followed by a strong post mixer amplifier Q22 The current drain in 022 can be reduced by the operator using a menu option that turns off Q12 A 5 pole variable bandwidth crystal filter is used on CW X7 X11 This filter 1s optimized for use at low bandwidths 200 to 500 Hz but can be set both narrower and wider as needed with only a small additional loss The shape factor and passband ripple content are optimized at around 300 Hz On SSB a separate fixed filter 15 switched in this filter is located on the SSB adapter AGC 15 derived from the output of amp by using an auxiliary low frequency of about 150 kHz see Control Board The AGC signal is then applied to pin 5 of the amp U12 A second crystal filter X6 X5 follows the I F amp to reduce wideband noise This filter is also tunable Varactor diode D39 s capacitance 15 increased during CW use but on SSB 15 reduced making the response
201. ntil you see ENT 0 9 then tap the number of the memory you wish to recall In both cases you can cancel the operation by tapping any non numeric switch Note If you hold rather than tap a numeric keypad digit when doing either a store or recall you will initiate scanning See page 99 Direct Frequency Entry To do direct frequency entry hold both and B AND simultaneously When you see on the LCD release the two switches then enter the target frequency using the numeric keypad To enter a frequency in the 160 meter band you must enter 5 digits starting with a leading 0 e g 0183 5 For other bands below 10 MHz you need only enter 4 digits e g 7040 On transverter bands direct frequency entry only be used to go to a new frequency within the present band see T RNx menu entry page 105 ELECRAFT There are three possible results from using direct frequency entry If you enter a frequency within the current band only the current VFO will be updated If you enter a frequency that 15 in a different band a band change results and the entire configuration for the target band will be loaded except that the current VFO will now be at the frequency you just entered If you enter a frequency that is too far outside any available band you ll be switched to the closest available band and the frequency will be set to the one last used o
202. o low for proper voltage regulation 011 No audio but display is OK 012 Display VFO knob switches or potentiometers do not function correctly or are intermittent 015 Current drain excessive on receive 016 Current drain excessive on transmit P7 on the control board may be jumpered for ext 12V Move the jumper to the 12V pos Battery voltage may be below 10 5V Recharge the battery as soon as possible If you saw INFO 010 on the LCD your battery voltage 1 too low lt 8 5V This usually happens on transmit when your battery is weak Disconnect the battery from the K2 and measure its voltage if the battery voltage quickly rises back to 11 or 12V the K2 may be loading the battery down But if the battery stays stabilizes at under about 10 V when measured outside of the K2 it has become fully discharged or may be defective If you suspect the K2 is pulling the voltage down tap any button to clear the INFO message then use DISPLAY to show the voltage and current drain If the current drain is gt 200 mA with no signal and the bargraph OFF something is shorting either the 12V line or one of the regulators 050 Make sure that a working antenna is connected check audio filter option antenna switch tuner SWR bridge etc See Receiver Troubleshooting 100 Front panel or control board may not be plugged in correctly Check the MCU 075 Check all regulated supply voltages 050 RP2 on the front
203. o protect the finish from dust and abrasion Use a sturdy packing carton with 3 or more of foam or shredded paper on all sides Seal the package with reinforced tape Neither Elecraft nor the carrier will accept liability for damage due to improper packaging Cover the to address label with clear tape so it will be weatherproof Finally call or send e mail to obtain the proper shipping address ELECRAFT Elecraft s 1 Year Limited Warranty This warranty is effective as of the date of first consumer purchase Before requesting warranty service you should complete the assembly carefully following all instructions in the manual What is covered During the first year after date of purchase Elecraft will replace defective parts free of charge post paid We will also correct any malfunction caused by defective parts and materials You must send the unit at your expense to Elecraft but we will pay return shipping What is not covered This warranty does not cover correction of assembly errors or misalignment repair of damage caused by misuse negligence or builder modifications or any performance malfunctions involving non Elecraft accessory equipment The use of acid core solder water soluble flux solder or any corrosive or conductive flux or solvent will void this warranty in its entirety Also not covered is reimbursement for loss of use inconvenience customer assembly or alignment time or cost of unauthorized service
204. o test the counter you can read the frequency of the 4 MHz oscillator on the Control board Touch the counter probe tip to the left side of trimmer capacitor C22 which 1 just below UI the microcontroller The LCD should now read within 02 kHz of 04000 00 Remove the frequency counter probe Audio Amplifier and Tone Generator Test Plug in a pair of low impedance 4 to 32 ohm headphones stereo or mono Tap MENU and scroll to the sidetone level menu entry ST L Hold to activate the sidetone You should now hear a clean 600 Hz audio tone Turning the VFO knob should vary the volume Notice that turning the AF GAIN control does not affect the sidetone volume The sidetone 15 injected into the AF amplifier after the volume control so AF GAIN affects only the receiver volume This is not a valid indication of how well the 4 MHz oscillator is calibrated since this oscillator is used as the reference for the frequency counter itself The 4 MHz counter will be calibrated in a later step ELECRAFT Tap MENU to turn off sidetone then scroll up to sidetone pitch menu entry ST P using the VFO knob or by tapping the switch The display will show ST P 0 60 This indicates that the sidetone pitch is set for 0 60 kHz 600 Hz Hold to turn on the sidetone then vary the VFO knob The pitch of the sidetone should change to match the display Keyer In the fo
205. off override ATU power limit turn FINE RIT on off see page 102 86 Using the Menu There are two menus primary and secondary You ll use the primary menu far more often see list at right The secondary menu is described starting at page 103 To access the menu Tap MENU The display will show the menu entry last used with an underline For example you might see LCD DAY indicating that the LCD is in day mode 1 backlight off You can scroll to a desired menu entry by turning the VFO knob or by tapping the and B AND switches To modify a menu entry s parameter Hold to move the underline to the parameter rather than the menu entry name In the case of LCD the parameter can be DAY or NITE Change the parameter using VFO knob or When you re finished tap MENU to return to scrolling Another tap of MENU will return you to normal operation DISPLAY Switch Usage in Mode The DISPLAY switch is used to access supplemental parameters when editing certain menu entries marked at right You will normally not need to change these settings Entries which use DISPLAY include Entry STL T R INP DISPLAY Switch Usage mode Selects the sidetone source U6 25 or U8 4 Use U8 4 default Specifies SR behavior 8r hold or 8r nor Hold mode default holds the 8R
206. olithic 103 530009 2 D2 D3 LCD Backlight Assy LED Backlights mounted in Diffuser 570004 1 D4 D5 D6 1N5817 BLACK E560008 3 kas 4 character 7 Segment multiplexed LCD 570003 1 10LED array Hi eff Green LED bargraph 570005 1 HW 2 Spacer Set made from 4 0 75 spacers for Backlight LEDs 1 Felt Washer 1 OD Mounts under main tuning knob 00033 1 100079 1 PCB stock spacing tool for push button switches FP to RF Board 620025 Page 1 Front Panel Appendix K2 Front Panel Board Parts List p n 50003 PICTURE Designators Value Description Part Number QTY Misc Keycap rect black Black keycaps for Push Buttons BLACK E980000 13 Misc Keycap rect gray Band up down 1 S3 GRAY E980027 2 Misc square black Lock Keycap S7 BLACK Square E980009 1 Q1 Q2 PN2222A Plastic Body TO 92 E580001 2 5K potentiometer B5K Keyer Speed Power Out Gain R1 R2 R4 R5 linear taper RIT XIT Offset E520004 4 Audio Gain Control E520003 1 4W 5 resistor TAN Color E500036T 1 AW 5 resistor TAN Color E500022T R9 1 AW 5 resistor TAN Color E500002T R11 1 4W 5 resistor TAN Color E500003T RS RT IVAW 5 resistor TAN Color ES00047T 815 5 resistor TAN Color ES00015T 516 5k 5 resistor TAN Color 500060 5 r
207. olled iron and limit soldering time to about 3 seconds per soldering attempt 53 AN In the following steps you ll install several toroidal inductors Use the number of turns indicated Do not attempt to alter the turns to match inductances specified in the parts list Sort the black and dark gray toroidal cores into three groups to avoid mis identifying them in later steps You should have eight FT37 43 ferrite cores 3 8 9 5 mm four T44 10 iron powder cores 0 44 11 mm and one FT50 43 ferrite core 0 5 12 7 mm Ferrite cores are dark gray T44 10 cores are black Locate a 3 8 9 5 mm diameter ferrite toroidal core type FT37 43 as described above Find RFC14 s component outline RF board near front left hand corner Compare this component outline to Figure 6 15 which shows two views of a typical toroidal inductor RFC14 will be mounted vertically as shown at the right side of the drawing with one wire exiting at the core s upper left and the other at the lower right There are pads on the PC board in these two locations Remove insulation Figure 6 15 Note Toroid illustrations such as the one above do not always show the actual number of turns used 54 To wind 14 cut a 9 23 cm length of 26 red enamel coated wire then sew the long end of the wire through the core exactly 10 times Each pass through the core counts as one turn The finished winding shou
208. on of the synthesizer receiver and other circuits on the RF board You can then use voltage tables resistance checks and close examination to find the bad component or connection Perform all measurements in the order listed In general your measurements can vary 20 25 from those shown and still be acceptable Space is provided to record your own measurements in pencil which will be very useful if you need to re test a particular circuit after repairs 10 Preparation for Receiver Signal Tracing 3 CA 10 Exit CAL FIL then select the 1 50 bandwidth filter using XFIL Verify that basic display and control circuits are functioning Using your DMM check the 5 V and 8 V regulator outputs Measure the voltages on the anodes right end of D6 and D7 on the RF board near the I O controller U1 In receive mode D6 s anode should be at about 8 V and D7 s should be near 0 V Connect the RF probe s output to your DMM s DC input jacks Select a 2 or 3 V DC range The DMM should read close to 0 000 V DC The reading should increase when you touch the RF probe tip with your finger Turn on the K2 and switch to 30 m or the appropriate band for your signal generator Select CW Normal mode Using the menu select OPT PERF Use CAL FIL to set up CW normal filter FL1 for a bandwidth of 1 50 If you can hear some noise on your receiver set up the BFO for this filter as described in the Operation section of the manual O
209. oning 075 If you suspect a ground short in any relay controlled circuit LPF BPF VCO you can simplify debugging by pulling out the control board then turning power ON and back OFF This places all relays in the RESET condition see schematic If you hear no relays on power up check the IOC 080 075 Possible MCU problem 080 IOC Problem Measure the voltage on pin 32 of the MCU U6 control board If it is not 5V check the 5V regulator 052 Remove the control board and carefully inspect the microprocessor Make sure it 15 not installed backwards has no bent pins and is seated firmly in its socket Verify that the MCU oscillator components all have the correct values and are soldered properly with no shorts X2 C21 C22 Listen for the 4 MHz oscillator signal using another ham band receiver If you can t hear the signal try putting a 1M resistor across X2 on the control board Also try rotating C22 If you saw the message INFO 080 the I O controller RF U1 or other auxBus device did not respond to messages from the main processor MCU Turn power OFF and back ON if you hear some relays switching on power up the IOC may be OK and the problem 15 likely to be with the AuxBus 081 If you do not hear any relays switching on power up your IOC RF U1 may be defective Inspect U1 carefully to see if you have installed it backwards or if any pins are bent Pull U1 out check its pins then re install it
210. ontrol board A shorting jumper should be installed onto the two pins of P7 nearest the P7 label For the remaining test and alignment steps you ll need a well regulated 12 14 V power supply or a battery A power supply rated at 300 mA or more of output current will suffice for the tests in Parts I and IL but higher currents 3 3 5 A will be needed for transmitter tests Part III If your power supply or battery does not already have plug that mates with the power jack J3 use the supplied mating plug and prepare a suitable power cable The center lead of the plug is positive Make sure K2 15 turned OFF power switch 51 out Plug your power supply or battery into J3 on the rear panel Fold the tilt stand out to improve the viewing angle if desired AN If you see or smell smoke when you turn the K2 on for the first time turn off power and disconnect the power supply immediately Normally you should hear the relays being reset by the I O controller Next nonvolatile configuration memory EEPROM will be initialized This process takes approximately 10 seconds During this period you should see INFO 201 on the LCD Displays of this kind are referred to as INFO messages and are used to alert you to possible problems In this case the info message 15 just a reminder that EEPROM has been initialized Turn on K2 using 51 After about 10 seconds you should see the default K2 frequency d
211. ontrol fully counter clockwise minimum gain 3 Select CAL S HI in the menu 4 Turn the VFO knob until the right most bargraph segment is just barely turned off 5 Exit CAL mode by tapping MENU Note The S meter must be recalibrated anytime the AGC threshold is changed The AGC threshold adjustment is described on page 47 VFO Linearization CAL PLL The CAL PLL function automatically calibrates VFO fine tuning You can repeat CAL PLL at any time although this should not normally be necessary One reason you might re run CAL PLL is after calibrating the frequency counter see Advanced Operating Features page 101 In general you ll need to re run CAL PLL and CAL FIL anytime you change the setting of C22 Control board which 1 used to align the 4 MHz crystal oscillator To Linearize the VFO Remove the top cover The bottom cover must be installed Allow a 10 minute warm up period at room temperature Connect the internal frequency counter cable to VCO Exit the menu if you were using it Switch to 40 meters and set the VFO anywhere in the 7000 7100 kHz range Use the menu to activate CAL PLL When calibration is completed 4 8 minutes you ll hear a short alert tone and see End on the LCD You can then tap any switch to return to normal operation ie be What you re actually calibrating is relationship between the PLL phase locked loop divider and the crystal reference oscillator
212. operation use the menu to select LCD DAY LCD backlight off and high brightness LED bargraph Indoors or at night use LCD NITE backlight on reduced bargraph brightness Bargraph Modes You have a choice of OFF DOT or BAR for the LED bargraph If you select DOT just one bargraph segment representing the current meter level will be illuminated If you select BAR all LED segments to the left of the current level will also be illuminated resulting in a more visible display OFF mode turns off the bargraph completely during receive but uses DOT mode on transmit see Advanced Operating Features Display Modes Tapping DISPLAY alternates between frequency display mode and voltage current display mode If you have the KAF2 or KDSP2 option installed audio filter and real time clock a time date display will also be accessible plus DSP settings in the case of the KDSP2 In frequency display mode the LCD will show the operating frequency mode indicator and any annunciators that are enabled e g 24945 04c This is the display you ll use most often In voltage current display mode the LCD will show supply voltage in 0 1 V increments and supply current in 0 02 A increments e g E13 811 40 This is useful for monitoring battery condition It can also be used with a simple voltage probe to check DC voltages inside the K2 Jumper P7 on the Control board selects either 12 monitoring or the voltage probe P5
213. ories for the target band using VFO A only Then choose one memory as the initializer to be used when starting channel scan and it Edit the RATES secondary menu parameter page 103 tap DISPLAY to select CH SC channel scan or CH SC TN channel scan plus manual hopping exit the menu this memory If manual hopping is enabled you can now use the VFO to hop among memories assigned to this band Scanning can be initiated via 98 or The scan rate 1s 0 2 seconds per channel 0 5 seconds per channel for live scanning Note VFO B can be set up differently on a per channel basis for split operation if desired or you can fine tune channels when necessary by turning on both RIT and 100 Reducing Current Drain for Portable Operation You can use any of the methods listed below to reduce receive mode current drain and thus extend battery life These techniques will have only a small effect on transmit current drain however Reduce power output to the lowest effective level if you re transmitting frequently on a weak battery Use headphones or reduce speaker volume Turn off the RF preamp Set GRPH to DOT mode There s also an OFF mode which completely disables the S meter and forces DOT mode for transmit power display Set OPT Optimization to BATT battery this reduces post mixer amplifier current by about 40 mA and automatically forces the bargraph to use DOT mode if set
214. ost characters To cancel FINE RIT Hold XFIL or change modes or bands FINE OFF will be displayed In data modes the TX and RX frequency will always be exactly the same if you use only FL1 if set to OP 1 and avoid using splits However you may wish to switch to a narrow filter when QRM is present The shift in frequency between OP 1 which is used on transmit and the narrow filter can cause the signal to walk up or down the band if net is turned on in the demodulation software Most software provides a means of turning off net 1 e locking the TX frequency FINE RIT provides a supplemental tool ELECRAFT Secondary Menu Functions To access the secondary menu tap MENU then tap DISPLAY You ll see SEC secondary menu functions are listed and described here Additional parameters accessed with DISPLAY during mode are marked see below SLCH Squelch level RATES RATE switch selections DOT Dot space ratio keying weight FPLY Fast Play switch selections PORT RS232 interface on off Port Test SPLT configuration Po28 10 12 meter SSB power output limit RTTY RTTY data mode control RTC Real time clock control RIT RIT XIT offset range up to 4 8 kHz ACC Accessory output control D19 Leave at default n unless K60XV option installed PA K2 100 final stage mode selection Fan Mode TRN1 3 4 6 Transverter band
215. ou have both a KAT2 and a KAT100 connected to your K2 the ATU menu entry will control only the KAT100 The KAT2 will be placed in through mode L and C 0 and will be set to antenna 1 The ATU is activated whenever you press The K2 display will show SWR or forward reflected power depending on the tuner s mode KPA100 is installed its TONE display will be used Power is reduced to 2 watts during TUNE mode 20 watts if the KPA100 is enabled This power reduction can be overridden by holding DISPLAY In this case no auto tune will be attempted Two antenna jacks are provided on both ATUs with the matching network data for both antennas stored on a per band basis You can tap ANT 1 2 to switch antennas Since the relays take only a small fraction of a second to switch it becomes practical to quickly try both antennas anytime the distant station is weak This 1s particularly useful for Field Day and similar contests where you might use two end fed random wires running in different directions Backup Timer While you re moving the VFO a 30 second data backup timer 1s being continuously re started Once you have completely stopped tuning the VFO for at least 30 seconds the K2 will then save your current operating frequency in EEPROM As long as you stay on a particular frequency no further updates will be done ELECRAFT CW Operation The K2 provides a number of features for the CW operator fast
216. ou have done the S meter adjustment as described above Using the menu select the LCD menu entry Change the parameter from NITE to DAY At this point you ll see the LCD backlight turn off and segment 10 of the LED bargraph will become much brighter Exit the menu and tap DISPLAY to switch to voltage current mode Write down the voltage and current readings Use the menu to change the GRPH mode to BAR 10 segments of the LED should now be on LJ Exit the menu and check the current It should now be about 0 16 to 0 18 amps higher Use the menu to change GRPH to DOT and LCD to NITE AN The combination of LCD DAY and GRPH BAR can result in high peak current drain on receive DOT or OFF are preferred for battery operation See Advanced Operating Features 48 Assembly Part II In this section you ll install the components for the synthesizer and receiver circuits Most of the components to be installed are on the front half of the board see Figure 6 1 After all of the parts are installed individual stages will be aligned and tested Detailed troubleshooting procedures are provided in the Troubleshooting section should you need them Appendix E The supplied RF probe will be very useful if you need to do signal tracing RF probe assembly instructions start on page 9 of Appendix E In some steps a large number of components will be installed then soldered as a group Check for unsoldered lea
217. ould be defective After checking DC voltages and transformer leads turn off power to the K2 and use your DMM s diode transistor test range to test the transistors With the DMM s positive lead on the base of Q7 you should measure about 0 6 k to the emitter or collector With the DMM s negative lead on the base of Q7 you should measure about 1 3 to the emitter and gt 3 k to the collector These also apply to Q8 DC Voltage Tables The tables on the following pages provide DC voltages for all ICs and transistors on each of the three boards as well as the diodes in the T R switch RF board Typically your readings will match these within 1096 The voltages were measured using a high impedance DMM 10 11 Megohm The K2 s internal voltmeter can also be used for most measurements Receive mode voltages are listed except as noted Most of the Control board measurements were made with the Front Panel module removed for easier access Exceptions are indicated by Equipment Setup Supply voltage 14 0 V no antenna LCD NITE GRPH DOT receive mode no headphones or speaker connected RF GAIN mid range AF GAIN minimum OFFSET mid range CONTROL BOARD Front panel removed except CAL FCTR mode w front Panel plugged in approximate and or may fluctuate Ref Pin VDC Ref Pin VDC_ Ref Pin VDC Ret Ref Pin VDC Qi E 80 02 E 63 U6 34 00 Logd 43
218. ould be oriented so that the hookup wire is connected to the side of P5 44 Move the voltage select jumper Control board P7 toward P5 Select voltage current display mode using DISPLAY switch The voltage reading on the LCD should go to 00 0 To test the voltage probe touch the tinned end of the hookup wire to pin 1 of the I O controller U1 RF board The voltage displayed on the LCD should be approximately 6 V Return the voltage select jumper to the 12 V position Note Always disconnect the voltage probe when it is not in use It may cause shorts or noise pickup if left inside the K2 during normal operation Menu Tutorial We ll present a brief tutorial on using the menu here A complete list of menu functions can be found in the Operation section Tap the switch on the K2 The first entry will be displayed ST L 040 This is the sidetone level menu entry 040 is the associated parameter in this case the sidetone volume setting The row of annunciators under ST L serves as an underline indicating that turning the VFO knob will change the menu entries Tap the MENU switch again and you ll return to the frequency voltage current display depending on what display mode was selected when you entered the menu ELECRAFT Tap MENU again to bring up the menu Turn the VFO knob now and you ll see the other menu entries and their parameters scroll by You can
219. ow keeping them flat against the PC board with no excess lead length D17 D21 and D22 are in the front left corner D29 through D34 are on the right side near the crystal filter __ DI7 221 222 D D30 D31 32 p33 D34 Install the 92 package transistors listed below Start with Q17 near the middle left edge Q17 2N7000 019 J310 Q25 PN2222A __ Q16 PN2222A Q20 2N7000 __ 018 J310 024 1310 Install Q21 2 5109 which is located near U1 in the middle of the board Align the small tab on the transistor s case with the tab on its component outline Bend the leads on the bottom to hold Q21 in place then solder Install 022 2N5109 which is to the right of the ELECRAFT label Make sure Q22 is flat against the board before soldering Carefully press 3 4 19 mm dia 0 25 6 4 mm high star heat sink onto Q22 The heat sink should be pressed down as far as it will go and should not touch the components around the transistor The heat sink is fragile If you need to spread it slightly use a blunted wooden pencil or a plastic wire nut Install 012 2N7000 which is to the right of 022 Install 023 2N7000 near the right front edge of board Install C167 001 102 which is near connector for the SSB adapter The leads on this capacitor should be formed to match its PC board outline ELECRAFT Sort
220. p against one of its stops place the knob at the top of the shaft and rotate it slowly the same direction while gently pressing it down ELECRAFT Attach small knobs to potentiometer shafts starting with the KEYER and POWER controls Each knob s two set screws can be tightened using the small Allen wrench 050 1 3 mm The knobs should be mounted as close as possible to the panel without touching it Align the pointers per panel labeling Locate 1 25 mm dia 1 16 1 6 mm thick felt washer and place it over encoder nut Figure 5 19 The washer should be seated on the front panel with the nut inside it Figure 5 19 Place the large knob on the encoder shaft Push the knob on until it just touches the felt washer If the knob does not spin freely move it out slightly If the knob is not contacting the felt washer at all it may drift slightly once it stops spinning Using larger Allen wrench 5 64 2 mm tighten two set screws alternately small increments AN At this point the pushbutton switches may not all protrude an equal distance The switch height will become equalized once the front panel assembly is mated to the RF board in a later step ELECRAFT 6 Board Most of the K2 s receiver and transmitter circuits are located on the RF board including filters oscillators and RF amplifiers The front panel and Control boards plug into the RF board a
221. panel board may be installed backwards Check receive mode current drain 140 Connect the K2 to a known 50 ohm load preferably a dummy load if current drain returns to normal you probably have a mismatched antenna and will have to improve the match or reduce output power If you have set the power level control significantly above the level that the transmitter is capable of current may 018 Supply voltage drops when K2 15 turned on 019 Supply voltage drops too low when transmitter 15 keyed 025 Battery won t charge up to the correct voltage or discharges too quickly 029 Small error in actual vs displayed frequency increase significantly try reducing the power setting or use CAL CUR to set up a current limit Use voltage current monitor mode to see if the power supply voltage drops below 11V on transmit if so you may be exceeding the capability of your power supply or battery 025 If the supply voltage and antenna impedance are correct the driver or PA transistors may not be operating efficiently 150 Use voltage current monitor mode to see if the receive mode current drain 1 too high 015 If voltage drops but current drain is normal you probably have a power supply problem or a battery that 1s not fully charged 025 review power supply requirements Specifications Use voltage current monitor mode to see if transmit mode current drain is too high 016 If voltage drops but current drain
222. parameter You can then tap DISPLAY to rotate through the parameters Finally change parameters as needed using the VFO knob or BAND Changes take effect when you exit EDIT mode ON OFF Set to ON to enable this transverter band RF Transverter operating frequency 0 999 MHz GHz digits not used IF K2 band to use as the 7 14 21 or 28 MHz OFS Display offset 9 99 kHz calibrate based on transverter oscillator offset if any OUT Power output limit L0 01 L 1 27 mW requires K60XV or H00 0 H12 7 watts can reduce setting using POWER control ADR Elecraft XV Series transverter selection address see K60XV manual When you first select a different I F the displayed A and B VFOs may end up outside the intended RF band To correct this tune the VFO up or down to the desired frequency or use direct frequency entry 105 Using transverter bands When you switch to a transverter band using B the message TRN1 2 or 3 is flashed The LCD shows up to 999 MHz by shifting one place to the right Note If you select 10 Hz tuning steps with RATE the hundreds of MHz digit will briefly disappear so you can see the 10 Hz digit Direct Frequency Entry on transverter bands 15 in band only For bands over 99 MHz the first digit is made part of the prompt For example on a transverter band in the 430 MHz range you d see
223. ponent outlines on the bottom of the board before proceeding Prepare the leads of Q7 as shown in Figure 6 31 Bend the leads upward away from the tab the opposite of the way you bent the leads of Q6 Form the leads using the shaft of a small screwdriver to create gradual bends Do not install Q7 yet aa um Figure 6 31 Insert a 4 40 x 1 2 12 7 mm screw through the PC board hole for Q7 s tab see Figure 6 31 Then slip the hardware listed below onto this mounting screw from the bottom side The shoulder washer can be found with the MISCELLANEOUS components __ 4 fibre washer black __ 1 4 6 4 mm dia 1 8 3 mm long phenolic standoff brown __ 4 nylon shoulder washer black AN Do not use any hardware other than that supplied The height of the PA transistor assembly is critical for maintaining good heat dissipation ELECRAFT Place Q7 bottom of board so leads are inserted into the PC board as indicated by Q7 s component outline The mounting screw and hardware should appear as shown in Figure 6 31 Do not solder yet Make sure smaller part of shoulder washer 15 visible through the hole in Q7 s metal tab Secure Q7 and its hardware temporarily using 4 40 nut and 4 lock washer Tighten the nut only finger tight Once Q7 and its hardware appears to be parallel to the board as shown in Figure 6 31 solder Q7 on the top of
224. r impedance The relays are rated at 5 V nominal 250 ohm coils The actual impressed voltage 15 in the 5 V to 6 V range depending on ambient temperature reflecting the best and worst case sink source current limits of the 16F872 The IOC communicates with the main microcontroller over the 1 wire AuxBus Ul s 4 MHz clock 1 turned off and the device 15 in sleep mode at all times except when it is processing an AuxBus message so there is digital noise on receive The main microcontroller runs from a 5 V supply while the IOC runs from 6 V The AuxBus is designed to accommodate devices running at both voltage levels Sheet 4 Transmitter Amplifier Q5 and are class A pre driver and driver stages respectively Q5 s bias 15 provided directly by the 8 V transmit line 8T while Q6 s bias 1 switched on by the 8T line but is gated by Q10 This is necessary because the DAC output that supplies the bias voltage for the driver 1s used as the crystal filter bandwidth control voltage on receive The bias to Q6 can be varied under firmware control to optimize efficiency for CW vs SSB and at different output levels This is useful in maintaining high overall efficiency during battery operation Q7 and Q8 form a conservatively rated push pull power amplifier that can easily supply 10 watts or higher output on all bands Q11 and Q13 are used as a bias voltage regulator The bias regulator is effectively out of the circuit on CW because of the l
225. r independent crystal filter settings for use with data modes To enable RTTY Data mode set the RT TY menu parameter to ON The MODE list will then include C L U andr r NORMAL mode uses lower sideband and r REVERSE with bar over uses upper sideband To select r REVERSE hold the switch FINE RIT 1 also very useful in data modes see page 102 Filter configuration CAL FIL r mode defaults to the same settings as LSB and USB Use CAL FIL on 17 meters or below to modify the r mode filter bandwidths or BFO settings as needed Speech compression SSBCr The SSBC menu entry will change to SSBCr when r mode is selected A setting of 1 1 1 1 or speech compression off 15 recommended for RTTY data ELECRAFT Real Time Clock RTC If RTC 1 set to ON and a KAF2 or KDSP2 option is installed the DISPLAY switch can access a time or date display The KDSP2 also provides DSP features which are accessible via the DISPLAY switch Refer to the KAF2 or KDSP2 manual RIT XIT Range Selection RIT RIT 1s used to select one of four RIT XIT OFFSET ranges If the selected range 1s 1 2 kHz or higher the RIT XIT annunciators flash whenever RIT or XIT are turned on Accessory Outputs ACC This menu entry can be used in conjunction with the Elecraft KRC2 programmable band decoder to control equipment external to the K2 Refer to the KRC2 manual for details Extended VFO Ra
226. ract 16085 19975 add 23085 add This includes capacitance of varactor diodes D23 D26 on all bands D21 D22 on 80 160 m and D19 D20 on 40 and 60 meters if applicable Only a portion of the indicated capacitance range is actually used to cover each Amateur band segment VCO frequency can be calculated based on a total inductance of 0 95 T5 in parallel with L 30 Based on an of 4915 kHz e g 6715 4915 1800 5250 kHz used as 60 meter lower band edge pending U S FCC ruling 40m ALT applies if D19 D20 are not installed COUNT PINS STARTING AT PIN 1 AND GOING COUNTER CLOCKWISE 8 PIN DIP SHOWN Special Symbols On bottom of PC board O O Jumper Elecraft By W Burdick Rev Date Sh E Swartz D 10 23 02 Appendix B K2 Schematic Key t 1 of 1 BANK1 BANK2 5A o 030 O O G 83 080000750200202000000 ol BAND DISPLAY 10 f e Ert D2 D5 MODE A B S8 VOX 9 REV 10 SPLIT 3 1 2 BANK1 D4 D3 Backlight m 30 25 20 1 LEDs i SBS 25155 DS1 o o o 9A Bargraph 02 Brightness Control VIM 838 DP 8 DIGIT LCD m m gt 29 Q lt lt a NOO BANK2 PRE ATTN AGC 11 spor 12 L cw Rev S13 05 D2 1 2 10 TUNE R11 ns ee LCD Driver U1 PCF8566 101 D6 D1
227. rage extends well beyond the ranges given in the table 15 MHz 15 used as the upper boundary on 20 meters to allow reception of WWV at this frequency If some VCO control voltage readings above are 1 5 V or some of them are gt 7 5 V you may be able to shift the entire set of readings so that they are all within the 1 5 to 7 5 V range Switch to the band and frequency that had the highest or lowest voltage then adjust L30 to bring that reading into range Then re measure all of the voltages to make sure they re in range AN If you have some voltages that are 1 5 V and others that are gt 7 5 V you have probably installed the wrong value at one or more of the VCO capacitors C71 C74 or varactor diodes D21 026 Another possibility is that TS has the wrong number of turns or that you installed the wrong type of slug tuned inductor at L30 If you change any of these components repeat the VCO alignment procedure L Disconnect the DMM from R30 Connect the internal frequency counter probe to the BFO test point TP2 right side of the RF board near the crystal filter 62 Test The beat frequency oscillator will be tested in the following steps L Switch to the 40 m band Connect the frequency counter to the BFO test point TP2 which is on the right side of the RF board near the crystal filter Using the menu select CAL The counter should show a frequency between 4908
228. re removed and option modules installed K160RX Component Installation optional Locate the Installation section of the K160RX kit manual Cross out the first three steps turning off the K2 removing hardware etc which are not applicable since the K2 15 already disassembled Skip the next two steps Do not remove WI Complete the steps for J14 through C13 and C14 Cross out next two steps examination of Q7 and Q8 The remaining steps should be completed after K2 alignment KSB2 Component Installation optional Locate KSB2 Module Installation in the KSB2 manual Complete only the steps required to install J11 J9 and J10 and the standoff Do not remove W2 W3 or C167 at this time Complete the remaining steps after alignment Other Option Component Installation optional If you have the 2 ATU or 100 Amplifier option install 2 pin connector P6 Use the option manual s instructions If you have the KBT2 Battery or KPA100 option install 2 pin connector P3 Use the option manual s instructions 71 If you have the KNB2 Noise Blanker option locate the Installation section of the KNB2 manual Complete only the installation of J12 and the standoff Do not remove W5 R88 R89 or R90 at this time AN Do not attempt to pre install parts supplied with the K60XV option The K2 must be completed and tested first Visual Inspection Examine the bo
229. return immediately to the receive frequency When using split experienced operators can simultaneously hold in the REV switch and adjust the VFO knob all with one hand to quickly find a clear spot to transmit 37 overrides VFO lock as described previously You can install an LED on the front panel that will turn on whenever SPLIT RIT or is effect See the associated application note Adding a SPLIT RIT XIT LED to the K2 94 RIT and XIT You can turn on RIT receive incremental tuning by tapping RIT The RIT annunciator then turns on It flashes slowly if you have selected a wide range RIT XIT offset see RIT menu entry page 104 The OFFSET knob controls the receive offset The 1 and 1 kHz marks on the offset control apply only if the RIT XIT range is set to 1 2 kHz using the RIT menu entry Regardless of the range used the exact offset can be determined by comparing the VFO frequencies with RIT on and off When XIT is turned on it works similarly to except that the transmit frequency 15 varied with the OFFSET control This can be useful for small split operation for example when a DX station you re listening to says to call UP 1 kHz or to adjust your transmitted frequency at the request of another station The transmitted frequency is not displayed during receive mode so if you need to determine the exact setting of the offset control when using you can brie
230. rovides receiver tuning in steps smaller than 10 Hz The primary use of FINE RIT 1 for data modes such as PSK31 which can benefit from a reduction in T R frequency shift between FL1 and one other filter FINE RIT mode is only effective for this if FL1 is configured as 1 SSB crystal filter FINE RIT can also be used to accurately zero beat AM stations or to fine tune CW signals when a narrow filter is used Limitations Entering FINE RIT mode turns off SPLIT RIT and XIT which cannot be used in combination with FINE RIT If you move the VFO while using FINE RIT you may need to readjust the OFFSET control due to small differences in linearity over the VFO s tuning range To use FINE RIT Select a narrow data mode filter FL2 FL4 using X FIL Next hold and X FIL together the display will show FINE ON and the RIT and XIT annunciators will alternate on off slowly Only FL 1 and the selected narrow filter will now be available the other two will be temporarily disabled You can then use the OFFSET knob to fine adjust the signal pitch of the narrow filter without affecting the pitch of FLI Turning the OFFSET knob will display the filter selection and the FINE RIT offset from 15 to 15 units e g 12 One unit is about 1 to 3 Hz finer on lower bands When you transmit always through OP 1 you will be closer to the received station s carrier frequency and on receive switching filters will result in few if any l
231. s are used on both receive and transmit it is possible to align all the remaining bands on transmit only However you can pre align the filters on receive by using a signal or noise generator such as the Elecraft N Gen separate ham transceiver or on air signals and atmospheric noise This pre alignment on receive will make transmitter alignment easier since the filter adjustments will already be at or close to their final values Switch to 80 meters and set the VFO for about 3750 kHz mid band Turn on the RF preamp by tapping P until you see the PRE annunciator turn on Use a signal generator or an antenna to inject a signal or noise at this frequency Adjust L3 and L4 for maximum signal strength AN Since some inductors are shared between two bands you must always align the remaining bands in the order indicated Always use this procedure if you re align the filters later ELECRAFT Switch to 20 meters 14100 kHz and turn on preamp Set C21 and C23 to their mid points Adjust L8 and L9 for maximum signal strength This step pre sets C21 C23 L8 and L9 before final adjustment in the next two steps Switch to 30 meters 10100 kHz and turn on the preamp Adjust L8 and L9 for maximum signal strength Switch back to 20 meters 14100 kHz Adjust C21 and C23 for maximum signal strength Switch to 15 meters 21100 kHz and turn preamp Adjust L10
232. s at right Scan Resume Scan mode users may wish to use the menu to program PF2 or 9 SCAN RESUME Holding that switch will method then re start scan without having to use the 99 use continuous scanning from VFO to VFO Setup VFOs A and B for the two ends of the band of interest VFO A must be set for a frequency ower than VFO B Select the operating mode preamp attenuator setting and tuning rate RATE Select a narrow filter if the band is noisy Store this setting in any memory using the switch but instead of tapping the switch for the desired memory hold the numbered switch until you see SCAN on the display You can also initiate scanning when you recall a stored memory Just hold then hold the numbered switch as with The memories can store up to 10 scan ranges for instant recall To scan with the receiver live unsquelched continue to hold the numbered button until you see AF ON If the tuning rate 15 set for 10 Hz steps live scanning proceeds at 50 kHz minute During squelched scanning when a station 15 found the receiver will un squelch and will stay on that frequency for about 25 seconds or until the signal fades You can stop scanning by tapping any switch key or PTT Use SCAN RESUME Or see at left to restart scan To resume live scanning hold until you see AF ON use channel hopping manually or with scanning Set up and 9 two or more mem
233. s inserted as indicated in Figure 6 19 b Pull the leads taut on the bottom then solder Sort the slug tuned shielded inductors into two groups 1 uH T1050 quantity 4 and 4 7 uH T1005 quantity 8 Install 4 7 uH inductors at 130 and 134 T1005 Press these inductors down as far as they ll go before soldering Install components listed below starting with C39 in back left corner near the key jack __ C39 001 102 C5 100 101 C7 100 101 __ CA 820 821 C9 001 102 __ 8 820 821 __ C108 01 103 _ W6 option bypass jumper IN4007 R38 1 BRN BLK RED __ D2 1N4007 __ 100 uH BRN BLK BRN C107 01 103 C110 01 103 _ D3 IN4007 Ds 1N4007 D4 1N4007 7 100 BRN BLK YEL R39 1 BRN BLK RED 109 01 103 C113 01 103 C114 01 103 _ WI option bypass jumper ELECRAFT Review Figure 4 2 before installing Q2 in the next step Q2 is a ZVN4424A transistor which has a slightly modified TO 92 package It is flat on both sides and the labeling may be on the smaller flat side The wider flat side must be aligned with the flat side of the component outline Install Q2 which is near C113 just installed Be sure to orient Q2 as shown in Figure 4 2 RFC3 is wound on an FT37 43 core dark gray using 16 turns of red enamel wire 12 30 cm Wind this inductor in the sa
234. s that must be permanently saved The EEPROM can be written millions of times without loss of data During normal operation on a single frequency such as when in a QSO the EEPROM is not accessed at all However whenever the VFO is moved a 30 second timer is triggered Once the VFO has stopped moving for 30 seconds the EEPROM 15 updated with the latest VFO frequency In this way the K2 always saves the most recent important frequency The EEPROM update also takes place any time you change bands or operating modes etc so you don t have to wait for 30 seconds to record an important configuration change An alternative strategy used by many rigs is to use battery backed up RAM continuously recording the operating frequency We preferred to eliminate the backup battery which often has a high failure rate and must be periodically replaced The Control board provides a built in voltmeter and ammeter By jumpering P7 appropriately the operator can monitor either the internal 12 V supply voltage or the voltage from a test probe plugged into P5 U3B buffers the DC signal from the probe and also is used in conjunction with Q11 to provide supply current monitoring The current sense resistor which has a value of 50 milliohms is located on the RF board R115 UA is a low dropout 8 V regulator which is stable with a K2 input DC voltage as low as 8 2 V Since all signal generating and signal monitoring stages in the K2 run from this 8 V supply
235. s to be installed in the next step are very sensitive to static discharge Touch a grounded surface before handling each IC Also note that U4 s label will read upside down pin 1 at the right when properly installed Install the following ICs Before soldering verify that the ICs are oriented correctly pin 1 associated with a round or oval pad _ U4 595 or TPIC6B595 U3 A6B595KA or TPIC6B595 U2 74 165 AN The bargraph LED will be installed in the following two steps This component must be seated flat on the PC board or it will interfere with final front panel assembly Also any misalignment will be visible from the front of the K2 Locate the bargraph LED DS2 The bargraph has a beveled corner or edge that indicates pin 1 Install DS2 as shown by its PC board outline just to the left of the LCD Bend two opposite corner pins slightly to hold it to the board then solder only these two pins If the bargraph is not perfectly flat against the PC board re heat the solder on the corner pins alternately while pressing it down Once it is in the correct position solder the remaining pins Remove any hardware supplied with the microphone jack J2 The nut and washer will not be used Install the microphone jack J2 in the lower left hand corner of the board with its polarizing nub at the top Figure 5 4 Press the jack down until it is completely flat against the PC board Re check the ori
236. see page 104 FINE RIT Fine RIT allows you to vary the receive frequency in increments smaller than 10 Hz This 1 especially useful with PSK31 and other narrow band data modes See page 102 ELECRAFT Advanced Operating Features A number of specialized operating techniques are described in this section Scanning and channel hopping see below Reducing current drain for portable operation Using a separate receive antenna Programming PF1 PF2 functions AGC on off control VFO frequency calibration techniques Checking firmware revision numbers Resetting to factory defaults Using computer control of the K2 FINE RIT mode Also see Secondary Menu Functions page 103 Scanning and Channel Hopping The K2 s scanning features let the K2 tune any band segment continuously or channel hop among two or more memories with or without the receiver squelched Scanning when squelched allows the K2 to ignore stable carriers key down signals with no modulation stopping only when interesting signals are found Scanning with the receiver live unsquelched is especially useful when listening for weak signals on very quiet bands 60 Meter Channels Channel hopping manually or using scan 15 intended primarily for use on 60 meters The present U S 60 meter channel designations are 5330 5 5346 5 5366 5 5371 5 and 5403 5 kHz USB only Typically these would be programmed into memories 1 5 See channel hopping detail
237. smitter to find where signal is lost see probe and procedure later in this section Check for any components getting hot Turn the K2 OFF and remove the heat sink inspect all parts and check for shorts or opens If you stay in key down ITUNE mode for several seconds it is normal to see some increase in power this is due to slow junction heating in the final amplifier transistors It is not indicative of a problem unless current drain is too high for the given power output If power goes up and down significantly during normal keying you may have a poorly matched antenna OR you may have power set too high for your battery or power supply to handle try reducing power to see if it stabilizes If you have seen a slow 10 20Hz oscillation superimposed on the transmitter s output signal it could be due to ALC modulation Increase the value of R98 RF board to the largest size that permits full output on 10 m If the transmitter 1 truly unstable 170 Output power drops to zero suddenly 175 Current drain too high on transmit or HI CUR warning 180 Keyer Problem oscillating even when connected to a 50 Q load you may have an incorrect component value or a toroid winding error go through the checks at 155 Make sure none of the diodes in the T R switch circuits are in backwards If you have transmit power set too high for your battery or power supply the supply voltage may drop so low on transmit that it resets the MCU CTRL U
238. ssembly sequence is important because later steps build on previous ones For example step 3 you ll put the modules together for the first time allowing you to try out the K2 s built in frequency counter The counter will then be used in step 4 to align and test the receiver and synthesizer on 40 meters In step 5 all the pieces will come together when you complete the transmitter and filters then align the K2 on all bands The last few details speaker tilt stand etc will be wrapped up in step 6 Unpacking and Inventory When you open the kit you should find the following items six chassis pieces Figure 3 1 three printed circuit boards Figure 3 2 FRONT PANEL board components bag CONTROL board components bag RF board components in two bags MISCELLANEOUS components bag includes hardware WIRE bag 4 ohm Speaker 5 small knobs and large tuning knob plastic tube containing the latching relays an envelope containing the LCD bezel green LED bargraph filter serial number label thermal insulators and other items Inventory We strongly recommend that you do an inventory of parts before beginning to assemble the kit It is not necessary to inventory the resistors which are supplied attached to tape in assembly order Even if you don t do an inventory it is helpful to familiarize yourself with the parts list Appendix A Additional information on identifying capacitor chokes and resistors is provided
239. st remember not to transmit into the KAT2 antenna jack that 1s connected to the transverter 106 9 Circuit Details Before reading this section you should become familiar with the schematics Appendix and Block Diagram Appendix System Overview The K2 s modular design allows flexibility in configuration and provides for future expansion At the core of this modular architecture are the three main circuit boards Front Panel Control Board RF Board User interface including display and controls MCU DC control AGC and AF amplifier All RF circuitry relays and I O controller IOC This functional division allows related circuits to be grouped together but also provides a high degree of isolation between the analog and digital sections of the transceiver The RF board serves as a mother board while the front panel and Control boards plug into the RF board at its front edge The front panel and Control boards are mounted back to back with their ground plane layers forming a partial enclosure that helps minimize radiated digital noise The K2 s custom enclosure is also modular It is fabricated in six pieces with a unique 2 D fastener used at each joint and also for PCB support This design provides a rugged but light weight enclosure that is ideal for field or home use The top cover which includes the upper portion of the rear panel can support a variety of built in options such as an internal battery autom
240. standoffs on the bottom of the board at the locations identified in Figure 6 3 Secure these standoffs from the top side with chassis screws and 4 lock washers Do not put lock washers between the bottom of the board and the standoffs Turn board back over to top side Install 28 pin IC socket at U1 near the middle of the board Figure 6 1 notched end of the socket should be at the left Make sure the socket is flat against the PC board before soldering U1 itself will be installed in a later step AN In the following steps you will install the latching relays K1 K17 Relay pins must not be bent or trimmed even after placement on the PC board as this may cause unreliable mechanical operation Since the pins cannot be bent to hold the relays on the board an alternative assembly technique using a flat surface must be used For this technique to work the relays must be installed before any of the taller components Place relays K1 K17 top side of RF board One end of each relay has a heavy line printed across the top to indicate the pin 1 end This end must be matched with the same end of the relay s PC board outline Do not solder the relays yet When all of the relays have been placed on the board lay a flat object such as a book or piece of cardboard on top of the relays to keep them in place then flip the board over Solder only two pins at opposite corners on each r
241. station without reducing the strength of the desired signal To switch to the opposite sideband hold the CW reverse switch A bar will appear above the mode letter C on the LCD Use first to stay on frequency when you switch to CW reverse Sidetone Pitch and Receive Offset When you change the sidetone pitch using the ST P menu entry you re also changing the CW receive offset The two always match within approximately 10 Hz This ensures that when you listen to other stations at same pitch as the sidetone your transmitted signal will be right on that station s frequency To see how the receive offset tracks the sidetone pitch Use to tune in a station at your current sidetone pitch as described earlier Then use ST P to change the pitch As soon as you exit the menu you ll notice that the station you were listening to has also been shifted to the new sidetone pitch Changing the sidetone pitch does not automatically re adjust the BFO frequencies in relation to the crystal filter passband So if you change your sidetone pitch you should use CAL FIL to manually optimize the BFO settings 98 SSB Operation You can receive SSB and data mode signals with a basic K2 but transmitting in these modes requires a KSB2 SSB adapter For complete details on SSB transmit refer to the KSB2 manual SSB Controls Operating Mode Use MODE to select L LSB U USB To alternate directly between USB and LSB use LSB is usual
242. t APPENDIX PARTS PLACEMENT 6 44 10111 APPENDIX 100 WATT STAGE AND RS232 I O K2 100 APPENDIX G SUPPLIED WITH KPA100 OPTION ELECRAFT 1 Introduction The Elecraft K2 is a high performance synthesized CW SSB transceiver that covers all HF bands It is a true dual purpose transceiver combining the operating features you d expect in a home station rig with the small size and weight of a rugged go anywhere portable The basic K2 operates on 80 10 meter CW and provides over 10 watts of RF output If you prefer a full power station you can complete your K2 as a K2 100 at any time by adding the internal 100 watt final stage KPA100 option Assembly of the KPA100 is covered in Appendix G a separate manual supplied with the KPA100 kit You can customize your K2 by choosing from a wide range of additional options SSB adapter with optimized 7 pole crystal filter Automatic antenna tuner 20 W internal or 150 W external 160 m adapter with receive antenna switch 60 m adapter with low level transverter interface Computer control interface RS232 Noise blanker Digital or analog audio filter each with real time clock Internal 2 9 Ah rechargeable battery Programmable band decoder High Performance VHF
243. t 2 l Attenuator Off Test Measure the signal at the end of R72 closest to 021 Expected 077 Vrms Actual 2 Preamp Off Test Measure the signal at the end of R73 closest to Z6 Expected 077 Vrms Actual Preamp gain will be tested later 3 Composite Mixer Output Measure the signal at the right end of R80 Expected 079 Vrms Actual 4 Post Mixer Amp Output Measure the signal at the case collector of Q22 2N5109 Expected 2 20 Vrms Actual 5 5 dB Pad Output Measure the signal at jumper W2 near the crystal filter Expected 1 40 Vrms Actual 6 Crystal Filter Output Touch the RF probe to jumper W3 near the crystal filter Adjust the VFO for a peak in the DMM reading Expected 0 35 Vrms Actual If this reading is low it may be due to a non optimal setting of the BFO in CAL FIL Try a different BFO setting then adjust the VFO for peak again and re measure the filter loss Note this measurement exaggerates the filter loss because the input to the filter is a composite of many signals besides the desired one 7 T7 Step Up Ratio Measure the signal at U12 pin 4 MC1350 Expected 0 4 0 8 Vrms Actual Note Limited by 240 241 8 Saturated Output Measure the signal at U12 pin 8 It may be anywhere between 0 00 and 0 30 Vrms Adjust the signal generator level until the DMM reads approx 0 15 Vrms If your signal generator is running from a 9 V battery you may have trouble getting the output
244. t soldering time for each pin to 3 seconds maximum 1 to 2 seconds should be adequate Install the 2 pin male connectors P5 and P6 As shown in Figure 4 5 the polarizing tab on each connector should be closest to the top edge of the board P5 the voltmeter input connector can be found near the upper left hand corner of the board P6 15 used for frequency counter input which 15 in the upper right hand corner lt Locking Tab Top side of PC Board Figure 4 5 17 Install the 10 pin dual row connector P4 to the left of P5 The short ends of the 10 pins are inserted into the board P5 must be seated flat on the board before soldering Install P7 a 3 pin male connector to the right of P5 The short ends of the 3 pins are inserted into the board Install a shorting jumper onto the two right hand pins of P7 At the upper left and right corners of the board are short jumpers labeled with ground symbols Use discarded component leads to make 3 4 19 mm long U shaped wires for each jumper Figure 4 6 Solder the jumpers on the bottom of the board with the top of the U shape approx 1 4 6 mm above the board a aaa a 4 Figure 4 6 LJ Locate the outlines for resistors RI8 and R19 on the bottom side of the Control board A The pads used for R18 and R19 are shared with connectors and J2 which are labeled on the top side of the board These connectors are provided wit
245. the MIC CONFIG header on the Front Panel board in order to transmit SSB on the K2 Most microphones with standard 8 pin connectors can be used Elecraft microphones include 8 small jumper blocks to simply installation On many mics the Up and Down buttons can be configured to switch between VFO A and B You ll hear one beep on switching to VFO A and two beeps when switching to VFO B RTTY Data Operation RTTY data operation can be accomplished in SSB modes by using AFSK audio frequency shift keying or other modulation modes Audio must be fed into the mic jack from a computer or modem and the K2 s audio output routed to the computer or modem from either the headphone or speaker jack Either LSB or USB can be used this will probably be determined by your software You can use either the SSB adapter s fixed filter OP 1 or the variable bandwidth crystal filter for receive purposes On transmit OP1 is always used since some RTTY data mode duty cycles approach 10096 you should reduce power to about 5W or avoid transmitting at 10W for longer than 1 2 minutes at a time Power levels above 10 W are not recommended You can key the transmitter via either the key jack or the mic jack since the DOT line is also the PTT line RTTY Data Mode mode letter This is a special fourth mode of operation that provides independent crystal filter selections for use with RTTY PSK31 etc For details on configuring and using RTTY data mode
246. the board Repeat steps above for the other PA transistor Q8 Uninstalled Components Check off components in list below verifying that they are not yet installed All of these components are on the top side of the board Note Most of these components are provided with option kits as indicated in the list Some of the connectors can be pre installed as will be explained on the next page __ near antenna jack supplied with K160RX C14 in 160 m band pass filter supplied with K160RX __ C75 synthesizer area supplied with K160RX __ J15 3 pin connector in 40 m band pass filter supplied with K60XV __ transverter conn near 40 m band pass filter supplied with K60X V __ 019 and D20 synthesizer area supplied with K60XV _ P6 near DC input jack supplied with or KPA100 __ P3 near crystal filter supplied with or KPA100 and J11 near crystal filter supplied with KSB2 __ 112 near crystal filter supplied with KNB2 __ J5 near BFO crystals reserved for future use __ X2 front left corner not used ELECRAFT AN If you have already purchased option kits you may install selected option components now as explained in the following steps This will simplify installation of the options after K2 alignment and test have been completed Do not remove the option bypass jumpers W1 W2 etc The K2 must be aligned and tested before the jumpers a
247. therwise set the BFO to the factory default value PLL Reference Oscillator and VCO RF board schematic sheet 1 2 Connect the RF probe s ground clip to the ground jumper near the synthesizer circuitry Reference Oscillator Output Measure the reference oscillator signal at pin 1 of U4 MC145170 which is near the front left corner of the RF board near the control board Expected 0 8 1 8 Vrms Actual VCO Output Measure the VCO signal at pin 3 of U3 LT1252 Expected 0 30 0 40 Vrms Actual If this signal 1s zero you may have the secondary winding of T5 reversed VCO Buffer Output Measure the signal on pin 6 of U3 Expected 0 60 0 75 Vrms Actual Check the VCO frequency RF Board Alignment and Test Part II BFO RF sheet 2 1 BFO Output Measure the signal U11 pin 6 NE602 Expected 0 20 0 70 Vrms Actual Use the menu to select CAL FCT R Press EDIT again to confirm the display will now show a frequency reading it will depend on where you have the frequency counter probe connected BFO Buffer Output Measure the amplitude of the signal at TP2 using the RF probe Expected 0 025 0 070 Vrms Actual Exit CAL FCTR Check the BFO frequency RF Board Alignment and Test Part II Low Pass Filter Bandpass Filter and T R Switch RF sheet 3 ie er nce 10 11 12 Turn both the attenuator and preamp OFF using Set RF GAIN to minimum Set AF GAIN to
248. this high Try running the generator from 12V or more in this case 9 2 Crystal Filter Output Measure the signal at U11 pin 1 NE602 Expected approx 0 27 Vrms Actual 10 Product Detector Saturated Output Measure the signal at U11 pin 5 NE602 Expected 0 58 Vrms Actual AGC Control Board l Disconnect RF probe from the DMM Connect the DMM s lead to chassis ground 2 Turn signal generator completely OFF remove its power Set RF GAIN to maximum 4 No Signal AGC Max IF Gain Measure the DC voltage on pin 1 of U2 LM833 Expected 3 6 V Actual 5 Set RF GAIN to minimum gt No Signal AGC Min IF Gain Measure the DC voltage on pin 1 of U2 Expected 4 6 V Actual Turn the signal generator back on AGC Saturation Measure the DC voltage on pin 1 of U2 Expected 6 9 V Actual Adjust the VFO to make sure this voltage is at its peak Amp AGC Input Measure the DC voltage on pin 5 of U12 sheet 2 Expected 5 0 V Actual Product Detector and AF Amp RF Sheet 2 1 Set up the DMM to read AC volts use 2 or 3 V meter range Touch the lead of the DMM to pin 5 of U11 NE602 Decrease the signal generator level until the AC voltage at pin 5 reads 025 Vrms The K2 s RF GAIN control should still be at minimum Disconnect the headphones and speaker Turn the AF GAIN control to maximum Measure the signal at the speaker jack P5 pin 1 n
249. to 14 V Actual Verify that the same voltage or slightly lower can be found on the case collector of Q5 and the tab collector of Q6 when the K2 is turned on and is in receive mode 9 10 11 12 13 If you don t have an RF probe you can build the one from Figure 1 Note do not use the RF probe to directly measure the transmitter s power output unless you have the power set for 2 W or less The IN34A diode in the RF probe may be damaged at higher power levels Test Shared Circuits Do the receiver signal tracing above This tests a number of circuits that are shared by both transmitter and receiver including the VCO BFO BFO buffer T R switches band pass filters and low pass filters It s important not to skip this step even if the receiver seems to be working correctly Shared circuits that are working marginally may affect the transmitter more than the receiver so their actual output levels must be measured Set up the K2 for 40 meters about 7100 kHz CW Normal mode Plug in a 50 ohm dummy load 10 W or higher rating Set the power level to 5 watts Connect a hand key or keyer paddle to the key jack Connect a speaker or headphones Use the menu to set ST L 030 ST P 0 50 and T R 0 05 Select hand key mode INP HAND Set up a transmit current limit of 2 50 amps using CAL CUR Basic voltage checks RF schematic sheet 2 Note When using to key the transmitter be sure to t
250. to the filter bandwidth display and B AND switches to the BFO display Tapping MENU exits CAL FIL and returns to the normal display On exit from CAL FIL changes are saved Turning Selected Filters Off FL2 3 or 4 can be individually disabled To turn off a filter display the filter bandwidth using CAL FIL then set the bandwidth number to OFF To get to OFF go to 0 00 first then turn the VFO knob a bit farther counter clockwise ELECRAFT 89 CAL FIL Example setting up all filters 5 Use XFIL to return to FL 1 Tap to show 6 Tap DISPLAY to show the actual BFO frequency Use the VFO Table 8 1 shows the recommended filer settings for a CW only knob to select the value shown in the table Typically you ll be K2 If you already have the SSB adapter installed use the SSB able to get to within 20 Hz of the target frequency settings from the KSB2 manual 7 Tap XFIL to save the new value and move to BF2 Repeat steps f 6 and 7 to set up BF2 and BF4 1 Read the CAL FIL instructions on the previous page if you 8 Switch to CW Reverse by holding Then repeat steps 6 haven t already You ll need to be familiar with CAL FIL and 7 for each CW Reverse BFO setting BF1 4 displays and controls before proceeding 9 Tap to return to the filter bandwidth display Use the 2 Do the Basic CAL FIL Setup from the previous page switch to select
251. tor and audio filter While this results in minimal parts count it was not considered since the resulting CW and AGC performance would have been poor On transmit signal flow is reversed so the BFO is combined with the VCO to generate an output at the operating frequency which is filtered by the band pass and low pass filters A highly stable power amplifier chain up to 10 15 watts on all bands and the output level can be set in 0 2 W increments 0 1 W increments below 10 W The transmit strip is conservatively rated to provide excellent reliability and immunity to high SWR High isolation PIN diode T R switching 15 used to provide silent no relays QSK Please refer to the RF Board section for further details ELECRAFT Coverage of 160 10 meters is provided by a single wide range VCO voltage controlled oscillator High side and low side injection are both used depending on the band so the overall VCO range is limited to about 6 to 24 MHz Only one VCO is needed with a single high Q inductor and three small DPDT relays configured to select one or more fixed capacitors The VCO 1s driven by a PLL synthesizer 5 kHz frequency steps are used at the PLL while 10 Hz increments are provided by a 12 bit DAC driving an 11 MHz VCXO PLL reference oscillator Crystal Filters and BFO Settings The signals you tune on the K2 s receiver are shaped by the crystal filter which passes only a narrow range of frequencies The pitch of thes
252. transistors 00030 4 40 screw 7 16 steel ZN Phillips for mounting feet and tilt stand 700032 6 4 40 standoff 1 4 long 3 16 Threaded 700026 5 4 40 standoff 1 2 x 1 4 Dia Threaded hex 0 5 x 0 25 dia 700007 2 N Shoulder washer nylon black For PA transistors 00001 2 Cable tie Small For speaker wiring and RF probe E980002 A HW Tilt stand set 4 feet Two oval front feet tilt stand two rear feet E980019 1 HW 4 washer fibre black For speaker and PA transistor mounting 700031 6 1 8 phone jack mono SPK J2 w switch Panel mount jack for ext speaker E620035 1 Page 1 Misc Probe Wire Appendix K2 Misc Bag Parts List 50004 PICTURE Designators Value Description Part Number 2 pin female conn SPK J1 Housing 0 1 spacing w locking ramp int speaker plug E620021 1 b ACC P1 Mates with DC power jack E620032 1 m P2 stereo 1 8 phone rasa for hand key keyer paddle computer input G 1 Msc 000 female crimp pins crimp pins For 2 pin speaker housing For 2 pin speaker housing SPK J1 J1 620022 2 n plastic tuning tool p n Misc MARS 12 For aligning slug tuned inductors GREEN E980012 1 Long handled for large knobs and for Control E ae Misc Allen wrench board removal E980004 1 Misc Allen wrench Short handled for small knobs E980008 1 Page 2 Misc Probe Wire Appendix K2 Misc Bag Parts List p n 8 50004
253. ttom solder side of the RF board carefully for unsoldered pins solder bridges or cold solder joints Since this 1s a large board you should break the examination up into three parts perimeter area __ front half __ back half Examine the top component side of the RF board for unsoldered pins solder bridges or cold solder joints This step is necessary because some components are installed on the bottom of the board and soldered on top Make sure switch S1 on the RF board is in the OFF position Plunger OUT is OFF Resistance Checks Perform the following resistance checks Res to GND gt 500 ohms 100 140 ohms 12 Install the two side panels and secure with two chassis screws each as you did in Part I and Part II Plug in the front panel assembly and make sure the connectors are completely mated Secure the front panel with four chassis screws Verify that all components on the bottom of the RF board have an installed height of 1 4 6 mm or less Capacitors that stand above this height must be bent downward so that they won t hit the bottom cover or heat sink Install the bottom cover and secure it using six chassis screws Plug in the Control board Make sure that all three connectors are completely mated Secure the front panel and Control boards together using two chassis screws Locate the heat sink panel You ll need to remove all of the masking tape fro
254. uding the liquid crystal display LCD LED bargraph push button switches and potentiometers See Appendix D for photos of the completed front panel assembly Components Open the bag labeled FRONT PANEL and sort the parts into groups resistors diodes capacitors etc Observe anti static precautions when handling ICs and transistors Locate the front panel PC board which 1 just a bit larger than the Control board It is labeled K2 FP on the top side in the lower right hand corner Assembly AN Your K2 s appearance and operation will be adversely affected 1f the controls or display are not mounted correctly and in the indicated sequence There are also special instructions for installing components on the bottom of the board Locate the Spacer Set PC board Figure 5 1 Using long nose pliers carefully break out the pushbutton switch spacing tool and the four backlight LED spacers Break the material only at the four indicated points Note The switch spacing tool doubles as the PC board for the RF probe which will be assembled later ELECRAFT Y Y Figure 5 1 Position pushbutton switches 51 and 52 as shown in Figure 5 2 using the switch spacing tool to set the switch height Make sure all four legs of each switch are centered in their holes then gently push each switch until it is resting flush against the switch spacing tool Caution switch pins are fragile Do not solder yet
255. ver in the area directly beneath L33 Electrical or other types of tape may be used ELECRAFT AN D40 and D41 were added to the receiver circuit to prevent saturation when a station a few feet away transmits on your frequency These diodes will be installed in the steps below L On the bottom of the RF board locate resistor R114 which is near the power switch Near R114 you ll find the 8 pads for I F amp U12 which is on the top side of the board Figure 6 23 Solder 240 and D41 to the two round pads just to the right of R114 pads 3 and 4 of T7 which is on the top side The banded ends of the diodes go in opposite directions 040 114 041 e Li EX U12 Figure 6 23 Visual Inspection Examine the bottom side of the RF board carefully for unsoldered pins solder bridges or cold solder joints Since this 1s a large board you should break the examination up into three parts __ perimeter of the board front half back half Examine top side in same manner Set SI on the RF board to OFF position Plunger OUT 59 Resistance Checks Perform the following resistance checks Res to GND R115 right end near 51 12V IN gt 500 ohms U6 pin 8 gt 100 ohms U6pin8 AN It s very important to re assemble the chassis as described below before attempting the alignment steps in the next section If you don t
256. written on it Record the number here This identifies the tested frequency of the crystals and can be used in aligning filters L Install the 12 096 MHz crystal X1 at the lower left The crystal should be seated flat on the board before soldering it is OK to bend the pins to hold it to the board X2 is not used To the left of X1 along the edge of the board you ll find a pad for grounding the crystal case Use short lengths of bare wire to ground the crystal on at the top of the can Install the BFO crystals at and X4 near J7 Important trim X3 s leads and fold them down flat against their pads before soldering Then use a minimal amount of solder This is necessary to avoid interference between X3 and L33 in a later step Ground the cases of X3 and X4 The ground pads are to the left of the crystals Install the 4 9136 MHz filter crystals at X5 through X11 Ground cases of X5 and X6 The ground pads are near where the two crystals meet A special grounding technique is required for X7 X11 There are two ground pads for each of these crystals one on either side Use bare wires 10 total for grounding the crystals as you did in previous steps but do not solder the wires to the tops of the crystals The wires must be soldered to the sides of the crystals instead about 1 4 6 mm up from the surface of the PC board Be very careful not to overheat the crystals Use a temperature contr
257. x 7150 kHz at an output level of about 100 dBm or strong enough to activate the S meter If you re using an antenna tune in a signal in the range of 7100 7200 kHz If you cannot find a signal you can use atmospheric noise from the antenna to peak the filter ELECRAFT Using the plastic tuning tool adjust both L1 and L2 back left corner for peak signal strength You may be able to use the bargraph if the signal is strong enough If you do not hear any signals or noise see Troubleshooting AN In CW mode the frequency shown on the display takes into account an offset equal to your sidetone pitch This allows you to determine a station s actual carrier frequency by matching their itch to your sidetone rather than by zero beating the signal The kera switch can be used for this purpose This completes 40 meter receiver alignment You may wish to become familiar with the K2 s receiver features before proceeding see Operation In Part you ll install the remaining band pass filters and align the transmitter and receiver on all bands Assembly Part In this final RF board assembly section you ll install the transmitter components as well as the remaining band pass and low pass filters This will allow you to align and test the K2 on all bands Turn off the K2 and disconnect the power supply Remove the two screws holding the Front Panel board to the Control board then unplug the Control board Use
258. y 101 being used by at least one count then return it to the original setting Tap IMENU to exit without switching filters This will force the K2 to re measure the BFO frequency 10 Repeat step 2 If the VFO dial is still off repeat steps 3 9 11 Modify a BFO settings using CAL FIL as in step 9 Firmware Revision Numbers You can check the K2 s main microcontroller and I O controller firmware revisions by holding any switch on power up Two numbers will then be displayed briefly For example you might see 2 04P 1 09 The first number is the main microcontroller s firmware revision and letter suffix The second number 1s the I O controller s firmware revision The KAT2 or KAT100 firmware revision is one of the parameters in the ATU submenu e g F1 00 The KPA100 firmware revision can be found in the PA submenu The KSB2 firmware revision can be obtained by first setting the SSBA menu entry to BAL then holding the switch Return the SSBA menu entry to its normal setting after checking the firmware revision The firmware revisions for other options may also be accessible refer to the individual option manuals 102 Resetting the Configuration to Factory Defaults You should reset configuration data to defaults only if the K2 s EEPROM 15 accidentally corrupted This is extremely unlikely to happen The most likely symptom that this has occurred would be an unexpected frequency setting showing up o
259. y break the 8V line to eliminate parts of the circuit in your search for the problem One example is RFC16 on the RF board If you lift one end of this inductor it will disconnect the entire synthesizer from the 8V line A number of circuits have resistors in series with the 8V line for example R112 in series with the I F amplifier U12 If you measure voltage on both sides of these resistors you may find a circuit that is drawing high current or is shorted Example If you measured 7V on one side of R112 and 3V on the other it would indicate that U12 had a current drain of 180 mA which is much too high I E R 4 22 0 18 060 No display on LCD 065 Relay Problem If the bar graph is also not working check the 5V regulator 052 Remove the front panel hardware and panel from the front panel PC board and inspect the entire board for shorts or incorrect components You may have LCD driver U1 in backwards or it may have a bent pin Check the values of R15 and R16 on the bottom of the board these resistors set the voltage for the LCD itself Re install the front panel board and turn on the K2 Using a voltmeter measure the voltages on pins 16 and 17 of front panel connector ICLK and IDA T These lines should show DC voltages between 0 and 5V due to data transmission from the microprocessor to the LCD driver If the voltages are fixed at either 0 V or 5V rather than being somewhere in between the MCU may not be functi
260. y small rectangles in Figure 6 6 Use one chassis screw to hold each fastener to the side panel see Figure 6 7 The two unused holes on each fastener must be offset away from the side panel ELECRAFT AN Since the K2 chassis is made up of a number of individual panels and fasteners you may need to loosen the fasteners and readjust them once or twice during assembly Attach the side panels to the RF board using two chassis screws per side panel The side panels are attached to the 2 D fasteners that are already in place on the RF board Figure 6 8 shows the approximate location of the two screws used to secure the right side panel Figure 6 8 39 Locate tilt stand which can be found in MISCELLANEOUS component bag It has three parts two oval feet and a tilt bail Figure 6 9 Note the screws that will be used to hold the tilt bail in place are not the black anodized type They are standard steel zinc plated screws 7 16 11 mm long so you won t confuse them with the 3 8 9 5 mm or 1 2 12 mm black screws Remove any masking tape from the bottom cover chassis piece Each oval foot has a notch into which the bail will be inserted Install one of the oval feet on the bottom cover using two 7 16 11 mm 4 40 screws 4 lock washers and 4 40 nuts The notch in the foot should be facing inwards toward the other foot The nuts and lock washers go on the inside of the bottom cover Instal
261. you have any difficulty with your K2 Closely examine all PC boards for poor solder joints and incorrect broken or missing components ook for your problem in the Troubleshooting Tables below Follow the step by step receiver and transmitter Signal Tracing procedures at the end of this section Also included are complete DC Voltage Tables for all ICs and transistors Troubleshooting Tables There are five troubleshooting tables listed below Within each table problems are identified by 3 digit numbers in the ranges shown In most cases you ll know which table to look in based on the symptoms you observe If in doubt start with the General Troubleshooting table General Troubleshooting 000 049 Control Circuits 050 099 Receiver 100 149 Transmitter 150 199 Operation and Alignment 200 249 When referring to components on the various K2 boards in the table we will sometimes use a shorthand form such as RF U11 which means U11 on the RF board INFO Messages If you see a message such INFO 100 on the LCD look up the corresponding entry in the troubleshooting tables Note INF O messages can be cleared by pressing any switch However the cause of these messages should be investigated before continuing to operate the transceiver General Troubleshooting 000 049 Problem 000 Unit appears to be completely dead when power switch 1 turned on no display no audio 003 LCD 15 dim 004 Display turns on but u

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