Service Manual
Contents
1. Et NT UT MX August 1984 CIT CRE a DOO IZ SP SP 605H SP 602H Synthesized VHF Portable Radio r n ta III I mm PP AA iten mm p m es Communications cast SEKCE se mah ain g A iy ES t e amp x V icta m y z E ators a i vw e NES My AIRE Lans rs si rd TRE TUE rr Sri E FU 3 F n N 7 P A8 INE a i lt 2 OR Re cep Myn TAZET TABLE OF CONTENTS Chapter 1 Specifications novem 1 Chapter 2 Operation 2 Chapter 3 Theory of Operation 3 Chapter 4 Frequency Programming 5 Chapter 5 Alignment Procedures 9 Chapter 6 Parts List 10 Chapter 7 Options 11 Block Diagram 12 Receiver Board Layout 13 PLL Transmitter Board Layout 14 SCNEMAUUC ee pata 15 10040 Mesa Rim Rd San Diego CA 92121 1 800 551 8551 1 800 424 8491 in California Local 619 587 0656 TLX 4993540 Copywrite 1987 m i Y a Es Rd wdi as Yat REN a h a ace DI TA PS DA LA ERA gt tam t rer rm n Pin Dl RA a a cm ae S tn tinta he Mn n mm im es m camas s air tr maa GE maa i in m Cam m T E d m or at CHAPTER 1 Specifications GENERAL Frequency Ranges SP 605H A 138 150 MHz SP 605H B 150 1602. Where Fo selected frequency For frequencies in the lower 5 MHz receive band adjust VC107 to obtain the proper frequency For frequencies in the upper 5 MHz receive band adjust VC108 to obtain the proper frequency For frequencies in the upper 3 MHz transmit band adjust VC106 to obtain the proper frequency RECEIVER ALIGNMENT Local Oscillator Connect an RF voltmeter to the source of receiver mixer TR222 Adjust L101 and L102 for maximum level If an RF voltmeter is not available L101 and L102 can be adjusted for best SINAD while feeding a high level on channel signal to the receiver Receiver Front End Alignment Input an on channel signal into the receiver and adjust L201 L204 for best SINAD This adjustment should be started on the center frequency of the programmed channels After setting L201 L204 the outside channels should be checked for proper specifications If outside the specified limits readjust L201 L204 for proper readings IF Detector Alignment These circuits are normally factory tuned and should not be retuned unless absolutely necessary If retuning is required adjust L205 and L206 for best SINAD Squelch Threshold Adjustment Connecta signal generator to the receiver and modulate the selected frequency with a 1 kHz tone set for 3 3 kHz deviation Set the ouptut level of the generator at 0 25uV Adjust the squelch control to maximum squelch position and adjust VR202 to open squelch After adjustment r
3. and RX2 X104 installed per order if specified Should ranging changes be necessary the above values should be installed according to the desired frequency ranges To order additional crystals specify the desired frequency from the above chart DIODE MATRIX PROGRAMMING Programming the desired frequency requires installation of diodes in the proper positions on the matrix board located at the back of the unit Matrix sections A through L correspond to the following channels Section RX Channel 1 Section G RX Channel 1 Section B RX Channel 2 Section H RX Channel 2 Section C RX Channel 3 Section RX Channel 3 Section D RX Channel 4 Section J RX Channel 4 Section E RX Channel 5 Section K RX Channel 5 Section F RX Channel 6 Section L RX Channel 6 TRANSMITTER PROGRAMMING Diode positioning for transmitter channels can be calculated using the following formula N TX X 5 fix X 2 X 400 where N diode programming position TX transmit frequency MHz fix ranging crystal frequency per chart 4 2 above il H Example Desired transmit frequency 155 00 MHz N TX X 5 ftx X 2 x 400 155 00 x 5 35 10 X 2 x 400 77 5 70 2 X 400 7 3 x 400 2920 li This resultant four digit number is then subjected to one of the following charts Chart 1 Chart 2 3000 N 2900 3999 gt N gt 3000 B3 2000 B3 2000 A3 1000 D2 800 D2 800 C2 400 C2 400 B2 200 B2 200 A2 1
4. 1 1 1 1 1 4 1 1 1 1 0 O 5 1 0 1 1 1 1 6 0 1 1 1 1 O 7 0 0 to 1 1 1 8 0 1 1 1 0 0 9 1 1 O 1 1 1 10 1 0 1 1 1 Q 11 0 1 0 1 1 1 12 1 0 1 1 0 0 13 O O 1 1 1 0 14 o 0 1 1 0 0 15 1 1 O 1 1 0 16 1 1 0 1 0 0 17 0 1 0 1 1 0 18 0 1 0 1 O 0 19 1 0 0 1 1 0 20 1 0 0 1 O O 21 0 0 0 1 1 0 22 0 0 0 1 0 0 23 1 1 1 O 1 0 24 1 1 1 0 0 0 25 0 1 1 0 1 0 26 0 1 1 0 O 0 27 1 0 1 0 1 0 28 1 0 1 0 0 0 29 O 0 1 0 1 0 30 O O 1 O O O 31 1 1 O O 1 0 32 1 1 0 O O O 33 0 1 0 O 1 0 34 0 1 0 0 0 0 35 1 0 0 0 1 0 36 1 0 O O O 0 37 0 0 0 0 1 0 38 O O O 0 0 0 Switch Settings VR 701 OFF 1 ON 0 DO D2 D4 i Ei Di D3 D5 Tone Encode Level Adjust Key transmitter and adjust VR701 for 500 575 Hz CTCSS tone deviation Check all frequencies and average accordingly PT 10L Schematic a Tt as ae tes ms e BR gt m as a de be 1702 1701 2 gt ere om bt olt we ue e Luc w dui 10K 10 18Vv VR701 we d us v e le 8710 56K t C dead lo sein PLL Transmitter Board Layout Receiver Board Layout 14 5024 25C5379 16658 25C3628 MIXER 245665 saw de CONT 4 258621 DC SV OUT PLL 2SK192 258621 y Sw lesa ntisx2 RX PINI26 esas 2502603 JR amp TTCHFEr 25c2605 444222 nS
5. 2scso19 2sc2zoss 2502724 2502753 21 4 MHz 1F AMP FILTER 21M15C2 12SC2724x2 PRE AMP j2sc260M2 MULT x2 iveco 2SC2724 2SK 92 LOOP FILTER P C 9 9 osc TC5082 ni 20 945 MHZ AY a s459KHi FILTER 10 24MHz PIN 2 AF AMP _ PIN 4 VOL TBAB20M j BUFF S cci BIO 25C2603 LIMITER AF AMP fesams 2802608 Mc301x3 DI gt TX RX APRE AMP 2Sc2603 f2SC2724x2 sw SE mies CH Sw e o COUNTER Teso8i tesiz2 foc AMP J2saiis 2sc2603 Block Diagram FREQ BANDO ddd ES PLL MIXER asc2724 135 140 2475 30 16 140 145 26 00 31 35 O 14 150 27 25 32 80 P ERN MN ost 250335 for Semi Duplex 150 155 28 50 33 85 155 160 28 75 35 10 160 165 31 00 gt 36 35 is 165 170 32 25 37 60 170 175 33 50 38 85 AZZ ZA A 153 156 28 25 34 60 TRIOS TR107 1 m TP104 RF LEVEL E i E Mina Pd TX RX 0 4V i hd i m RX E TR O 5V U ORE i ky TRIOS 17 1620 TR223 TR224 T 1 3 3 E ad L Tin ECHANICAL PARTS EXPLOSION A
6. a semi duplex split is accomplished by using a different crystal frequency at the pre mix oscillator Mixer and Low Pass Filter The mixer circuit of TR1 13 mixes the VCO frequency with the output of the pre mix oscillator TR115 The desired resultant which is the difference frequency or lower frequency component is passed by the low pass filter consisting of CH108 C1 77 and C178 Pre Mix Local Oscillator In order to reduce the VCO to a frequency suitable for division by the low speed logic the VCO output is mixed with the output of the oscillator C mbler TR115 In the receive mode the VCO output must be offset from the transmit frequency by half of the first IF frequency This and a semi duplex split is accomplished by using a different crystal frequency at the pre mix oscillator Divider Buffer The output of the low pass filter is buffered and amplified by TR114 to the level regired by programmable divider lC101 Programmable Divider Division of the buffered pre mix output is accomplished by programmable divider IC101 The division ratio is set by the programming diodes on the diode matrix board This division process determines the output of the VCO E Phase Comparator Reference Oscillator Divider By comparing the divided VCO frequency to the reference oscillator the synthesizer can determine if the VCO is on the proper operating frequency as determined by the programming diodes If a difference is detected the
7. 00 A2 100 D1 80 D1 80 C1 40 C1 40 B1 20 B1 20 A1 10 A1 10 DO 8 DO 8 CO 4 GO 4 BO 2 BO 2 AO 1 AO 1 Locations B3 AO refer to diode locations on the diode matrix soard By installing the proper diodes according to the calculated number the synthesizer provides the proper divide ratio allowing the VCO to operate on the proper freguency gt Example Calculated number for N 2920 The binary equivalent for 2920 is determined as follows B3 A3 D2 A2 D1 A1 DO AO 2 9 2 O Diode programming would then then be determined as B3 D2 A2 B1 Installation of the above diodes will program the transmit freguency of 155 00 MHz RECEIVER PROGRAMMING Programming of the receiver diodes is similar to the transmitter The only difference in the procedure is the applied formula For receiver programming the following formula is used N RX 21 4 X 5 frx X 2 x 400 where N diode programming position RX receive frequency MHz frx ranging crystal frequency per chart 4 2 above Example Desired receive frequency 157 750 MHz N RX 21 4 X 5 frx x 2 x 400 157 750 21 4 x 5 29 75 x 2 x 400 136 35 X 5 59 50 x 400 68 175 59 50 x 400 8 675 x 400 3470 li Il By referring to the above charts the programming diodes needed would be 3 4 7 O B3 A3 C2 C1 B1 A1 Installation of diodes B3 A3 C2 C1 B1 and A1 wili progr
8. DC tuning voltage will be changed to drive the VCO to the correct output The DC tuning voltage is derived from the filtered output of phase comparator IC103 Output from IC103 represents the difference between the divided output of programmable divider IC101 and the 2 5 kHz output from the reference oscillator divider IC 102 The 2 5 kHz reference signal is derived from the 10 240 Mhz reference oscillator and a fixed division ratio in the reference divider of 4096 Any detected difference will alter the DC tuning voltage to bring the VCO output to the correct frequency CHAPTER4 Freguency Programming GENERAL INFORMATION Frequency programming for the SP 605H is accomplished by the proper installation of diodes on the diode matrix board located in the back of the unit Each unit is shipped with a sufficient supply of diodes to program all six channels In addition to diode programming each unit must have the proper ranging crystals installed There are two RX crystals X103 and X104 and one TX crystal X 102 RANGING CRYSTAL SELECTION The following chart provides the proper frequency for the RX and TX crystals RX X103 amp X104 Frequency Band MHz TX X102 135 140 140 145 26 00 31 35 145 150 27 25 32 60 150 155 28 50 33 85 155 160 29 75 35 10 160 165 31 00 36 35 165 170 32 25 37 60 170 175 153 158 Note SP 605H units are shipped from the factory with RX1 X103
9. MHz SP 605H C 160 170 MHz SP 605H D 170 175 MHz Number of Channels 6 Programming Synthesized oupply Voltage 12 VDC Current Drain TX 1100 mA RX 90 mA Standby 25 MA TRANSMITTER eee e maa RF Power Output 5 1 watt Frequency Stability o PPM 30 C to 60 C Duty Cycle 1096 Spurious amp Harmonics 60 dB Transmitter Rise Time 40 ms Audio Frequency Response Pin 3 1 3 dB from a 6 dB per octave pre emphasis from 300 3000 Hz su i ill la lla 71 AT R Sensitivity 35 uV 12 dB SINAD 70 dB Selectivity 7 5 KHz Modulation Acceptance t2 5 KHz with NBF Option i 65 dB Spurious Rejection unsguelched Receiver Attack Time o PPM 30 C to 60 C Frequency Stability 1 3 dB from a 6 dB per octave Audio Freguency Response Pin 10 de emphasis from 300 3000 Hz Audio Output 500 mW OPTIONS PT 10L Single tone encoder decoder CTCSS NBFV Narrow band filter for 12 5 KHz channel spacing CHAFTER 2 BASIC DFERATING FROCEDURES z 1 GENERAL INFORMATION The SF 605H and SF 602H portable transceivers are the first all metal synthesized low cost handhelds specifically designed for the professional land mobile user These units operate in the VHF FM band from 136 MHz to 174 MHz The specific frequency of operation is determined by the diode matrix board and the corresponding ranging crystal By eliminating the need of frequency crystals for each channel future channel additions are easily a
10. NTROL Once the desired volume level is set the squelch control should be rotated counter clockwise until the background noise just disappears Rotation beyond this point will elevate the squelch threshold and weak transmissions may be missed By periodically adjusting the squelch control clockwise referred to as breaking sguelch the user can perform an operational check of the receiver and speaker system 2 24 PTT SWITCH To transmit from the portable the press to talk FTT switch on the side of the unit must be pressed This action engages the transmitter and disables the receiver When transmitting the user should speak across the face of the unit within a few inches of the speaker At the end of the transmission the FTT switch must be released to enable the receiver ee HI LO FOWER SWITCH For extended battery life it is recommended that the radio be operated in the LO power position whenever possible This reduces the output power of the transmitter and saves battery drain during transmissions However if the LO setting does not provide sufficient range the switch can be placed in the HI position This allows maximum output power from the transmitter 2 26 TRANSMITTER INDICATOR When the transmitter is engaged the transmitter light will illuminate to indicate transmitter power If the light fails to come on during transmissions the unit should be checked by a technician for proper operation 2 27 BATTE
11. RY INDICATOR When the battery pack is nearing a discharged condition the Dattery indicator light will illuminate When this occurs the battery pack should be replaced or recharged CHAPTER 3 Theory of Operation RECEIVER Antenna Switching Received signal enters the antenna connector and passes through the low pass filter network into the RF amplifier stage TR221 When the unit is in the transmit mode the transmitted signal is prevented from entering the RF amplifier stage by the antenna switch diodes D103 and D104 tn the receive mode these diodes are non conductive and decouple the TX final stage RF Amplifier L201 and L202 allow input filtering and imp dance matching to the first amplifier stage of TR221 TR221 is a dual gate MOSFET which provides ampiification of the incoming signal First Mixer After amplification the receive signal enters the first mixer stage of TR222 where an injec tion signal at 21 4 MHz offset is provided This FET helps assure minimum intermodulation interference and maximum linearity After mixing with the received signal the resultant 21 4 MHz signal with accompanying modulation is fed to the first IF stage of crystal filter FL201 First IF Amplifier FL201 reduces any incoming harmonics and provides impedance matching to the IF amplifier stages of TR223 and TR224 Second Mixer Second Local Oscillator Limiter Detector The circuitry centered around multi function IC201 co
12. am the receive frequency of 157 750 MHz RANGING CRYSTAL SWITCHING An additional diode location exists in each section of the matrix board These locations next to the AO position of each section are for the purpose of crystal Switching into operationRX1 or RX2 Location A corresponds to channel 1 B corresponds to channel 2 etc If all locations are left empty RX1 will be Switched into the circuitry Whenever a channel assignment requires the ranging of crystal RX2 a diode should be installed into the proper location channel assignment Location Diode Installed Crystal Used Example A CH 1 NO RX1 B CH 2 NO RX1 C CH 3 YES RX2 D CH 4 YES RX2 E CH 5 NO RX1 F CH 6 Note Locations G through L are unused DIODE INSTALLATION The programming diodes should be carefully formed and installed with a low temperature soldering iron As many diodes must be housed in a small location care must be taken to assure that all diodes are installed neatly and with equal spacing RX RX RX RX RX TX Tx Tx TX TA K A ICH 8 2CH C XH RX O 4CH E 5CH F KH H J 4CH SH Tx U KH G ICH 2CH 3CH 0 E E H F I E912 6 BB E O Da 19 190 Dia OBE O 1 O Oiv gt ANOAVA QHVOS XIHLVW CHAPTER 5 Alignment Procedures PRELIMINARY Alignment of the SP 605H should be performed by aualifi
13. ccommodated and the delay time of waiting for crystals is eliminated Flower output for the SP 605H is five watts in the HI position and one watt in the LO position The SP 602H provides two watts of RF output in the HI position and 0 5 watts in the LO setting Hy utilizing the LO power position whenever pos sible the battery consumption is reduced to allow longer use between battery charges battery power for the SP 605H is provided by a slip on 12 0 volt pack The SF 602H uses a smaller pack of the same style with a voltage of 7 2 volts Both of these battery packs are easily changed by the user For optimum performance these nickel cadmium packs should be completely discharged periodically prior to recharges This allows the battery to take on a deeper charge which offers a longer use before minimum operating voltage is reached J FERATING FROCEDURES 2 21 ANTENNA The helical whip 59 ohm antenna is secured to the portable at the HNC connector To install the antenna the connectors should be mated and the connector turned clockwise until locked cece VOLUME CONTROL When the volume control is in the full counter clockwise position the unit is in the OFF position To turn the unit ON the control should be turned clockwise until the desired volume level is reached To assure the proper setting the squelch control should be set to its full clockwise position to allow noise to be heard from the speaker aco SQUELCH CO
14. d by TR205 TR203 and TR203 The amplified audio is then fed to limiter TR202 which prevents overmodulation After limiting the audio is then routed to low pass filter TR201 This integrator circuit prevents splatter into the transmitter Modulator Audio from the speech amplifier is applied to the VCO FET TR110 which causes the carrier frequency to be shifted proportionaliy to the audio rate This action causes frequency modulation of the transmitter Audio level is controlled by deviation control VR201 Transmit data input pin 7 of the inter face connector is fed to the base of TR110 through R123 Buffer Multiplier Driver Final Isolation for the VCO injection signal is provided by buffer TR102 The VCO frequency at this point is half the channel frequency The multiplier circuit of TR103 doubles the input frequency and passes the transmitter signal into buffer TR104 Preamplifier TR105 amplifies the signal to an adequate level to drive the final power amplifier TR106 During transmit mode the antenna switch diodes D103 and D104 are forward biased to allow passage of the transmitter RF Also during transmit condition light emitting diode D301 is forward biased to indicate transmitter operation SYNTHESI2ER The primary function of the synthesizer is to provide transmitter injection signal and local oscillator signal to the receiver This design allows a single crystal osciliator to provide stable frequency generation without t
15. ed technicians only Warranty may be void if technical repair is attempted by anyone that is not trained and familiar with portable communications equipment Alignment of the SP 605H can easily be accomplished with standard test equipment However the equipment should be within calibration standards to assure accurate alignment of the radio equipment PHASE LOCKED LOOP PLL Connect an oscilloscope to TP101 and adjust L118 for maximum signal in receive mode at this point Once this is accomplished turn the core of the coil down one turn to broaden the adjustment This adjustment should be accomplished on the lowest frequency tha the unit is programmed to operate With the unit on the lowest programmed receive frequency connect a DC voltmeter to TP103 top of R120 and adjust L114 for 1 28 VDC Connect a wattmeter to the antenna jack Then key the transmitter on the lowest frequency and increase this voltage until the transmit power appears Connect an oscilloscope to TP104 and adjust L119 for 1 0 to 1 6 volts peak to peak in the transmit mode After this adjustment recheck the DC voltage at TP103 to assure that the voltage is less than 3 0 VDC in the transmit mode If the reading is greater perform the above procedure for L114 again Connect a frequency counter to TP105 and adjust the following variable capacitors to obtain the proper frequency 200 Hz according to the following calculation RX Fo 21 4 x 5 TX Fox 5
16. emove the input signal to the receiver and rotate the squelch control to assure that the radio is squelched within the first quarter turn of the control 10 TRANSMITTER ALIGNMENT Preliminary Connect a wattmeter of suitable range to the antenna connector Adjust VC104 and VC105 to mid position Check air coils L106 L108 and L1 10 to assure that none of the coils are shorted Transmitter Buffer Alignment Set the channel selector to center frequency of the programmed frequencies Connect a DC voltmeter to TP102 and adjust L103 and L104 to peak voltage reading in transmit mode Continue this procedure until maximum voltage is obtained However the cores should not be above the top of the cans lf this occurs reset the cores to mid position and readjust Adjust VC101 to maximum voltage at TP102 Retrim adjustments L103 L104 and VC101 to obtain maximum voltage Driver and Final Power AMP Alignment Activate the transmitter on the radio s center frequency and adjust VC102 VC103 VC104 and VC105 for maximum power output If power output degrades on outside channels decrease VC 105 slightly and retune VC102 VC104 LO Power Setting Adjustment Set the LO power switch SW301 to the LO position and adjust VR101 to the desired output factory set for 1 watt Modulator Alignment Set the transmitter in the HI position and modulate the transmitter Adjust VR201 for 4 8 kHz of deviation Check the LO pow
17. er setting to assure that the modulation remains the same Power Supply Check To assure proper operation the SP 605H TM should not exceed the following current drain specifications Model Supply Voltage Mode Maximum Current SP 605k 12 0 VDC TX Hi 12A SP 605H 12 0 VDC TX LO 450 mA SP 605H 12 0 VDC RX 90 mA In the event that current drain is substantially greater than the above values the unit should be retuned and or checked for defect te 2 t ar sogno tw a s ty i A 2 Y v0 i 1 4 ye 4 oe a ud o Vo CER deducit ta s Y dA r 4 we 1 E oa Pa 05 x is ys Parts List GENERAL INFORMATION The schematics in Chapter 8 incorporate all component values along with the schematic identification number These values or manufacturer part numbers should be used when replacing defective parts ORDERING INFORMATION When ordering replacement parts from the factory simply use the following nomenclature Model Schematic Identification Example SP 605H TR106 This part number would coordinate to the final transistor TR106 in the transmitter of a model SP 605H Any changes in component values or manufacturer s part numbers will be coordinated at the factory to assure that the proper part is replaced CHAPTER 7 Options SINGLE TONE CTCSS ENCODER DECODER PT 10L Tone Data Chart Tone Fred Data tin La Tone Hz DO DI D2 D3 D4 D5 1 1 1 1 1 1 1 2 1 1 1 1 1 O 3 O
18. he need for tuning crystals for each channel By dividing the reference oscillator Signal by an amount respective of the selected channel the synthesizer can provide a range of frequencies Programming of the synthesizer is accomplished via the diode matrix board located at the back of the unit These diodes determine the proper divide ratio for the synthesizer Refer to diode programming instruc tions in chapter 4 j The design used in the SP 605H TM is a premix PLL Configuration which allows a lower frequency output from the VCO This is desired to allow accurate division by the digital divider circuitry Voltage Controlled Oscillator VCO The VCO consists of oscillator TR110 and varactor diode D106 The effective capacitance of D106 is controlled by the DC tuning voltage As the tuning voltage is changed the oscillator frequency of the VCO follows The output of the VCO is applied to the doubler circuits of TR101 and TR103 TR101 feeds the receiver and TR103 provides signal into the transmitter The VCO output is also applied to cascaded buffer stages TR111 and TR112 which feed the mixer circuit for the phased locked loop PLL Pre Mix Local Oscillator In order to reduce the VCO to a frequency suitable for division by the low speed logic the VCO output is mixed with the output of the oscillator doubler TR115 in the receive mode the VCO output must be offset from the transmit frequency by half of the first IF frequency This and
19. nstitute the second mixer stage second local oscillator limiter and detector An internal oscillator signal of 21 945 MHz is mixed with the incoming signal of 21 4 MHz The resultant 455 kHz signal is routed outboard to FL202 which reduces any harmonics and provides a clean signal for return into IC201 Upon entering 1C201 the 455 kHz signal is limited to assure stable output This limited signal is then fed through a quadrature detector to strip the modulation and provide audio output from IC201 Discriminator output pin 2 of the interface connector is obtained from pin 4 of 1C201 Squelch Circuit Squelch threshold is established by control of an active filter within IC201 This threshold is determined by the position of squelch potentiometer VR301 When no carrier is present allow ing high frequency noise to be received the internal filter passes this high frequency signal into rectifier diode D208 The resultant voltage is used to control the gating transistors of TR225 TR227 This action reduces the power output of the audio stage IC202 When a carrier is present the gating circuit enables the final audio stage Audio Amplifier The output from IC201 is routed through volume potentiometer VR302 to the audio amplifier stage of IC202 The output of this stage is available through pin 4 of the interface connector or J303 TRANSMITTER Transmit Audio Amplifier Transmit audio pin 12 of the interface connector is preamplifie
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