SERVICE MANUAL CHANGE NOTICE
Contents
1. n Q102 z Ww E c17 e z ews Sl puo S C109 R118 C111 a lors T8288 e Em 2 laos R286 V105 z mm 118 2 U102 RI BE ojo te mnl ainina U106 R114 R113 cmol ZSSS C114 Shorted with a 0 Q resistor on F board versions and later D102 Id S103 Digital Display Board LJ Digital Display Board Side 1 Side 2 R242 R296 r ve R2029 m 4 c281 31 zx gt vend R245 3 E em 282 8 ag ms R259 L202 Gp mus m R211 272 3 R enf caso 1 C249 0205 Tum S R254 U208 E m 8236 8237 S C215 D207 R297 C279 14 E CSS Se 2 Uni Iu C244 R294 8557 R238 R239 gt t R215 S o L2. bole R109 W104 102 6103 R104 cr eo c5 Ic gH C 108 J104 SIDE 1 R106 RIOZ Shorted with 0 Q resistor R108 Io z I A delgls CBA J104 0102 z J ECU e C17 mp E cios S p01 e C109 R118 Cit J O O T 2 r50103 R286 V05 3 qm C118 2 U102 EE ARS RS uia R114 R113 ei else C114 SIDE 2 U1 U1L Body Pack Transmitter Digital Display Board Legends and Foils E and Earlier Board Versions 25C1021 BG 27 Replacement Parts and Drawings Shure U1 U1L Body Pack UHF Transmitter n fh op NL
3. U1 U1L Body Pack Transmitter Digital Display Board Legends and Foils F and Later Board Versions Replacement Parts and Drawings 28 25C1021 BG Shure U1 U1L Body Pack UHF Transmitter nm a
4. R202 r3 1 e C281 2 tl 282 z R259 ojd S 3 3 S R211 gozn os CS o ale im R254 257 IR2S8R239 s Q ey Ret ig du mss C261 C245 eg 2051 IS e NO sls BIS S sen lsiz 2 R248 ele S gIR204 om seis C230 SINN o e N 3 BIS 9o STTrR251 erea un P15 P16 on L205 C62 020 C254 C x 0 R222 z S8 R T2 fg ezz S SIDE 2 S o B S L208 C226 R221 Z0Z0 U1 U1L Body Pack Transmitter R Audio Printed Circuit Board Legends G and Later Board Versions Replacement Parts and Drawings 30 2501021 BG Shure U1 U1L Body Pack UHF Transmitter FTD ER RB Gc E OK La GE ILE x zo es co co x J2X J2 W3 W2 WI LEMO 4 Pin TINI QG 4 Pin Mic Jack Printed Circuit Board Legends and Foils 25C1021 BG 31 Replacement Parts and Drawings Shure U1 U1L Body Pack UHF Transmitter Notes This page intentionally left blank Replacement Parts and Drawings 32 25C1021 BG
5. AUDIO ANALYZER U1 Transmitter Audio Analyzer Power 2 5 Vdc Measurement AC level Gain Minimum for JB models Output None set to MAX Filters Low Pass 30 kHz OFF High Pass 400 Hz OFF Figure 9 Tone Key Level Adjustment Test Set Up 1 Use adc power supply to apply 2 5 0 01 V to the battery terminals with no audio applied to the audio input 2 Make sure no filters are used on the measuring instrument 3 The tone key frequency will be approximately 32 768 kHz Adjust R224 so that the tone key level of 22 8 0 1 dBu 56 mV is measured at U202 pin 1 For JB models this level should be 24 7 dBu 0 1 dBu 45 mV Service Procedures 18 25C1021 BG Shure U1 U1L Body Pack UHF Transmitter Bench Checks Dc Problems Rf Problems 25C1021 BG z WMeasure the dc voltage at pin 1 of C104 This is the output of the dc to dc converter It should be 5V 0 2 Vdc z WMeasure the dc voltage at C113 pin 1 and C105 pin 1 It should be 5V 0 2 V 1 Nerify the battery voltage is between 2 V and 3 5 V 2 Check for proper Vcc and 5 V rf at Q207 make all dc measure ments with respect to rf ground unless otherwise specified If incorrect voltage is present check the values of the biasing resistors Trace the dc back to the dc to dc converter 2 Check the power swit
6. Figure 6 U1 Power Output Measurement Test Set Up 1 Rf output power is not adjustable Use RG58 or any other low loss 50 Q cables for all rf connections 2 Include the insertion loss of the cables and connectors in rf conductive power measurements 3 Using the spectrum analyzer verify output power is at least 8 dBm JB models must be at least 8 dBm and cannot exceed 10 dBm 25C 1021 BG 15 Service Procedures Shure U1 U1L Body Pack UHF Transmitter Audio Alignment Deviation Reference Voltage NOTE DC VOLTAGES ARE PRESENT E m Of o AT MOST RF TEST POINTS USE A Fo ll DC BLOCK ON THE RF SIGNAL S201 o GENERATOR TO PROTECT TONE KEY o TEST EQUIPMENT Say TN U4 RECEIVER m z PAR I E o D ICE amd k FL DC BLOCK RF SIGNAL GENERATOR AUDIO ANALYZER Oo Oo S85 dee 3 228 222 3 BESSESE oo ca um m EB OCOC Em Em Oo zn Felt J c3 Oo U4 Receiver Audio Analyzer Rf Signal Generator Output Unbalanced Measurement AC level INT FM Gain Maximum Filters INT 1 kHz Squelch Mid Low Pass 30 kHz ON Output Amplitude 50 dBm Tone Key S201 OFF High Pass 400 Hz ON Figure 7 Deviation Reference Voltage Test Set Up Using a U4 Receiver 1 2 The U1 transmitter should be turne
7. GROUP CHANNEL he Li SENE 10 D 1 Antenna oe U 2 Programmable Display 3 Input Connector 8 SET Button U1L uses LEMO connectors 9 Audio Gain Control 4 ON OFF Switch 10 Battery Cover Release Tabs 5 On Off LED 11 Battery Compartment Cover 6 Belt Clip 12 Battery Fuel Gauge 7 MODE Button 13 Battery Compartment Figure 1 U1 UL Transmitter Controls and Indicators Service Note Shure recommends that all service procedures be performed by a Factory Authorized Service Center or that the product be returned directly to Shure Brothers Inc Licensing Operation may require a user license Frequency or power output modifications may violate this product s approvals Contact your country s communications authorities 3999 Shure Incorporated Printed in U S A 25B1021 BG Shure U1 U1L Body Pack UHF Transmitter Circuit Description Audio Section Audio enters L201 an inductor that is used as an rf choke The signal enters a 6 dB pad made up of R203 R204 C204 and C206 The signal is ac coupled through C205 into a 40 dB 30 dB for JB frequencies user adjustable gain stage around U201A This gain stage is externally accessible to the user C201 C202 and C207 protect the pre amplifier and bias circuits from rf interference R205 an
8. SIDE 1 c S J3 C216 S C281 be 2 4 8 S _ C282 a s 2 R259 SIE aS 3 a R211 Ww l I Tun Q R29 8ozn m VIS S e NR S C215 ce zol z R254 Rasy R258 R239 QA ER UO pag C261 C245 eg 203 SS R255 ojo I2 Gne R240 Cm e R206 len No No iss BI S 8 Ems R248 o 7 za ig e Ss TEE x o RISS 9 T8251 S p10 P15 P16 n L205 C62 LAAS W Eee e es C254 8 e R222 2 BC a S S co Q CCS co SIDE 2 an o X ES L208 C226 R221 COZO U1 U1L Body Pack Transmitter RF Audio Printed Circuit Board Legends E and Earlier Board Versions 2501021 BG 29 Replacement Parts and Drawings Shure U1 U1L Body Pack UHF Transmitter SIDE 1 Q201 C224 R219 cd NO co n CA
9. R256 im TST 16205 0201 5 RE R255 C261 C245 IG S18 up RES C238 Lc R240 Bi g Rods 2 ES 9 Riele Ens R 2 S S amp L sw20 6S5 S E RM A quao SiedR204 o ny N Tr ES 3 B SS Em S S PiQ PI5 P16 205 exa c4 S o R22 On F S z 9203 SN S E OnF Me 225 5 By board gir S S Woo D Q20 E i versions and later d L208 C226 R221 0202 and later Rf Audio Board Rf Audio Board Side 1 Side 2 Mic Jack Board TINI Q G 4 Pin Mic Jack Board LEMO 4 Pin Figure 2 Test Component Locations 25C1021 BG 5 Preliminary Tests Shure U1 U1L Body Pack UHF Transmitter Listening Test Before completely disassembling the transmitter operate it to deter mine whether it is functioning normally and try to duplicate the reported malfunction Refer to the User Guide for operating instructions trouble shooting and specifications Review any customer complaint or request and focus the listening test on any reported problem The following more extensive functional tests require partial disassembly Functional Tests Refer to the Disassembly section to partially disassemble the transmitter for the following functional tests Use dc blocks at all rf outputs to protect test equipment Test Setup 1 Use a U4 receiver for the following functional tests 2 Dc voltages are present at most rf test points Use dc blocks to protect the test equipment if necessary 3 Conn
10. inch 11 wire ribbon cable and one male Shure 170A07 and one female Shure 170A08 surface mount connector Note that the SMC connectors face in opposite directions Female SMC connector wi Figure 4 Printed Circuit Board Interconnecting Cable Male SMC connector on back side 25C1021 BG 13 Service Procedures Shure U1 U1L Body Pack UHF Transmitter Rf Alignment FREQUENCY COUNTER 9 R201 R243 CH2 J104 J200 O C239 U201 gt u202 C CH1 eu m n R224 J3 l U1 Transmitter Frequency Counter Power 8103 ON Connect CH2 J3 Gain R201 For JB models Set to maximum Figure 5 Alignment Test Set Up Rf Alignment Set Up 1 Proper adaptors should be used to connect the test equipment 2 Use RGB8 or other low loss 50 Q cables for all rf connections 3 Include the insertion loss of the cables and connectors in rf conductive power measurements 4 Connectthe rf audio board to the digital board through board interconnects J104 and J200 5 Onall models except JB audio GAIN potentiometer R201 does not need to be preset to any position On JB models R201 GAIN should be set to maximum 6 All rf measurements should be made from the antenna output connectio
11. strength The tone key feature indicates battery level at the receiver It is not available on JB models The tone key signal along with the processed audio signal is fed to summing amplifier U202A Resistors R232 and R233 set up a half supply bias Resistor R231 located at the output of the summing amplifier pre vents spurious oscillations from the operational amplifier After passing through ac coupling capacitor C232 the signal is fed to the rf module Circuit Description 2 25C1021 BG Rf Section 25C1021 BG Shure U1 U1L Body Pack UHF Transmitter Processed audio enters R243 an internal potentiometer adjusted for 45 kHz deviation 10096 modulation with a 7 2 dBV 1 kHz tone at the output of the front audio stage pin 1 of U201 On JB models R243 is adjusted for 5 kHz deviation with 63 2 dBV 1 kHz tone at the input to the transmitter The audio is then fed to the tuning voltage pin of the voltage controlled oscillator VCO and modulates the carrier directly The use of a phase locked loop PLL frequency synthesized system eliminates the need for multiplier stages resulting in a much higher degree of spectral purity The VCO is shielded against interference from external rf fields Regulated 5 Vdc power from the dc to dc converter ensures frequency stability even if the battery voltage changes At the output of VCO U205 the rf signal splits into two paths The output of the VCO is coupled by C244 to the fr
12. 3 dB Conversion Chart OdBV 2 2dBu OdBu OdBm assuming the load 600 Q Test Equipment Most test equipment needed is described in the Shure Wireless Service Equipment Manual The following test equipment or approved equivalent is also needed Table 1 Test Equipment Equipment Type Model Audio analyzer Hewlett Packard 8903B Digital multimeter Fluke 87 Interconnect Cable Shure PT1843 BNC Male Cables 2 Shure PT1838A DC Blocker Shure PT1838W BNC Female to 1 4 inch Phone Plug Adapter Shure PT1838C 20 dB Attenuator Shure PT1838T BNC to QG Cable Shure PT1825 BNC to LEMO Cable Shure PT1878 BNC Female to SMC Female Adapter Shure PT1838S BNC Female to SMC Female Adapter Shure PT1838S Test Cable Japan Version Shure PT1838 AF Adapter Japan Version Shure PT1838 AJ BNC Male to RG 174 Cable unterminated Shure PT1824 Hewlett Packard 53181A Hewlett Packard 8656B Hewlett Packard 8590L Shure U4S Frequency counter Rf signal generator Spectrum analyzer Shure U4S receiver Audio levels in dBu are marked as dBm on the HP8903B Printed Circuit Board Interconnecting Cable This cable is provided with the standard test equipment and is used to connect U1 circuit boards that have been removed from the case for servicing It is made from two custom Shure printed circuit boards a four
13. 8 L200 205 208 211 Inductor 10 0 18 uH 162R10 Q102 Transistor MOS FET MDT3055EL 183A35 Q103 202 204 Transistor NPN SOT 23 MMBT5089L 183A38 Q207 209 Transistor PNP SOT 23 MMBT5087 183A01 Q208 Transistor Dual Gate Ga As MESFET NE25139 183C12 SW201 Switch 3 position 155A09 U102 Comparator 188A136 U105 Integrated Circuit 5 V dc dc converter 188A182 MAX751CSA U106 Voltage detector 188B210 U208 Dual operational amplifier 188A118 Variations in part numbers correspond to country codes Table 6 U101 EPROM Table Country Code Shure Part Number UA 188T131UA UB 188T131UB MA 188T131MA MB 188T131MB MC 188T131MC MD 188T131MD JB 188T131JB KK 188T131KK Replacement Parts and Drawings 24 2501021 BG 25C1021 BG Shure U1 U1L Body Pack UHF Transmitter Table 7 VCO Selection Country Code UA205 VCO Range Shure Part Number UA 782 810 MHz 187A10R MA MC JB KK 837 863 MHz 187B10R MB 800 830 MHz 187C10R MD UB 692 716 MHz 187D10R Table 8 Microwave Isolator Selection UA207 Shure Part Number Country Code UA 187A07 MA MB MC MD JB KK 187B07 UB 187C07 25 Replacement Parts and Drawings Shure U1 U1L Body Pack UHF Transmitter This page intentionally left blank Replacement Parts and Drawings 26 25C1021 BG Shure U1 U1L Body Pack UHF Transmitter
14. Shure Incorporated 222 Hartrey Avenue Evanston IL 60202 3696 U S A UHF Wireless System SERVICE MANUAL CHANGE NOTICE U1 U1L UHF BODY PACK TRANSMITTER Changes and corrections have been made to the Service Manual for the U1 U1L UHF Body Pack Trans mitter These changes will make it easier to repair the transmitters To update your Service Manual remove the pages identified in the tables below and replace them with the pages attached to this Change Notice Note that there are no changes to pages not specifically identified in the tables below U1 U1L SERVICE MANUAL REVISION HISTORY CHANGES EFFECTIVE JULY 12 2002 REMOVE INSERT these pages from the these Revised pages into the U1 U1L Service Manual U1 U1L Service Manual 21 to 25 21 to 25 2000 Shure Incorporated Printed in U S A 25 1021 2 BG SHURE U1 U1L Body Pack UHF Transmitter General Characteristics The Shure U1 U1L Body Pack UHF Transmitter is a microprocessor controlled body pack transmitter operating in the UHF frequency range This product is intended for use in high end installed sound rental and concert sound applications Different frequency variations are available Controls and Indicators GO Diet q NOTE All models shipped after February 1999 have a soldered attached antenna to replace the Screw on removable antenna ES O O
15. ch 2 Look for open coils cracked parts reversed polarity capacitors solder shorts If there is a short to ground from 5 V isolate differ ent parts of the circuit z NVerify rf OFF signal changes from 5 V at power on power off to 0 V during normal operation Trace the signal to the microproces sor Q207 should be saturated during normal operation z Nerify that the battery voltage appears at U105 pin 1 z Verify that the Vds drain to source voltage of Q101 is approxi mately 0 025 V Q101 should be saturated z NVerify that the dc to dc converter output is 5 V at pin 8 on U105 1 7if the carrier is out of specification by less than 40 kHz and cannot be corrected by adjusting C239 check the values of C239 C238 and Y201 If these values are correct replace Y201 As a last resort replace synthesizer U204 y lf the carrier frequency is not within the allocated UHF band width or if it is unstable the loop is unlocked Check the solder connections at the head board VCO microprocessor traces LE D and CK and synthesizer U204 2 Check for 4 MHz frequency at pins 1 and 2 of U204 If frequency other than 4 MHz is detected replace crystal Y201 2 Check the loop filter R238 C245 R240 C266 C267 R239 C247 U208 R243 and R285 z Check U204 pins 3 and 4 and U208 pin 8 2 Replace synthesizer U204 The tuning voltage of the VCO should be approximately 3 Vdc when the transmitter is pro gramm
16. d OFF for this procedure Connect the rf signal generator to antenna A or B on a U4 receiver Make sure the dc block is on the rf signal generator Set the rf signal generator to the same frequency as the U1 transmitter Set rf signal generator modulation to 1 kHz and set the deviation to 45 kHz for UA UB MA MB MC and MD models 40 kHz for KK models and 5 kHz for II models Set the output amplitude of the rf signal generator to 50 dBm Turn the U4 receiver ON and set the tone key switch S201 inside the U4 receiver to the OFF position This will disable the receiver tone key function Connect the audio analyzer to the unbalanced output of the U4 receiver The voltage should be 4 2 0 5 dBu 1 26 0 07 V for UA MA MB MC MD and KK models and 26 2 0 5 dBu for Il models Note the voltage obtained it is the deviation reference voltage 8 Service Procedures Disconnect the rf signal generator from the U4 receiver and return the tone key switch S201 to the ON position 16 25C1021 BG Shure U1 U1L Body Pack UHF Transmitter Deviation Reference Voltage Adjustment U4 RECEIVER fs Te e e t 20 dB PAD DC BLOCK ERE AUDIO ANALYZER ao z NOTE DC VOLTAGES ARE PRESENT a AT MOST FF TEST POINTS USE A o o o2 p000 77 DC BLOCK ON THE RF SIGNAL Oo Seon c o GENERATOR TO PROTECT o o 22 0000 coco o TEST EQUIPMENT U1 Transmitter Audio Analyzer P
17. d R207 set up a half supply bias and R206 sets the ac input impedance The amplified audio signal is then passed through a pre emphasis network before entering the compression stage R208 R211 and C211 set up two corners for the pre emphasis network The pre emphasis network boosts the high frequencies before transmission and helps set the hinge point 0 dB gain of the compandor The network feeds NE575 compandor U203 which utilizes an external amplifier U202B The com pandor performs 2 1 logarithmic compression of the audio signal Transistors Q201 and Q202 along with crystal Y202 form the tone key oscillator circuit which provides a stable continuous 32 768 kHz sine wave Transistor Q204 buffers the tone key signal before it is added to the audio signal The tone key signal is used in the receiver to provide audio output only when the tone key signal is present in the transmitted signal Therefore if the tone key or the transmitter is turned off the receiver will be muted Q203 acts as a switch for toggling the tone key on and off It is controlled via the microprocessor R224 allows the tone key amplitude level to be set The tone key circuit is powered by U208B which is a dc amplifier that multiplies the 3 V battery voltage to 4 5 V gain 1 5 As the battery voltage drops the tone key supply voltage also drops which decreases oscillator amplitude The tone key amplitude is used by the receiver to indicate transmitter battery
18. e U4 unbalanced output is within 2 dB with respect to the 1 kHz level Change the frequency to 10 kHz Verify that the measurement from the U4 unbalanced output is within 2 dB with respect to the 1 kHz level 7 Preliminary Tests Shure U1 U1L Body Pack UHF Transmitter Notes This page intentionally left blank Notes 8 25C1021 BG Shure U1 U1L Body Pack UHF Transmitter Disassembly and Assembly A ATTENTION Observe precautions when handling this static sensitive device Disassembly NOTE All models shipped after February 1999 have a soldered attached antenna to replace the screw on removable antenna Do not try to remove and replace the soldered attached antennas 1 Open the battery compartment cover and remove the batteries 2 Remove the belt clip 3 Remove the two screws from the back of the case 4 Lift the top half of the transmitter case away to expose the printed circuit boards 5 Remove the two screws securing the battery nest to the chassis 6 Remove the rf ground screw located next to the antenna 7 Lift the printed circuit boards out of the case TOP COVER RF SHIELDING GASKET BATTERY NEST __ _ DIGITAL DISPLAY CIRCUIT BOARD RF GROUND SCREW RF AUDIO CIRCUIT BOARD ANTENNA BATTERY COMPARTMENT COVER D CONDUCTIVE WASHER SLIPS OVER ANTENNA NOTE All mod
19. e mount with 1 10 W rating and 1 tolerance Capacitors Unless otherwise noted non polarized capacitors are surface mount NPO dielectric types with a 100 V capacity and a 5 tolerance and polarized capacitors are tantalum types 25C1021 BG 21 Replacement Parts and Drawings Shure U1 U1L Body Pack UHF Transmitter Table 3 U1 U1L Transmitter Replacement Parts Reference Shure Part Designation Description Number A1 Belt clip assembly 90A4392 MP1 Antenna removable units shipped before 2 99 95A8731 MP2 Antenna soldered units shipped after 2 99 70A8019 MP3 Battery nest 95A8751 MP4 Battery nest screw 30K8136A MP5 Bushing 66A308 MP6 Case back 32A8034A MP7 Case door 32A8025A MP8 Case top 32A8021A MP9 Coil spring 44A8012 MP10 Conductive gasket 8008198 MP11 Door spring 65A8243 MP12 Foam pad 36A675 MP13 Hinge pin 31A8142 MP14 Lens 65A8236 MP15 LCD liquid crystal display 95A8934 MP16 Nameplate 39B8227 MP17 Nameplate battery 39 8411 MP19 Retainer plate 53A8419 MP20 EMI Washer for use with 95A8731 antenna only 36B8066 Replacement Parts and Drawings 22 25C1021 BG Shure U1 U1L Body Pack UHF Transmitter Table 4 Printed Circuit Board Replacement Parts Side 1 Reference Shure Part Designation Description Number Non SMT Components MP21 Mic PCB Ribbon Cable 95A8622 J101 102 Socket stri
20. ect the power supply terminal through a milliammeter to the contact on the battery nest and the power supply terminal to the contact on the battery nest 4 Connect a dc voltmeter across the power supply and set the power supply for 3 Vdc 5 Connect the audio generator to the mic jack board either via the TINI QG connector or the LEMO connector to BNC cable depending on mic style Rf Power 1 Attach a U4 antenna to the spectrum analyzer 2 Turn the U1 on and hold it very close to the antenna Move the U1 up and down to maximize power on the spectrum analyzer 3 Verify that output power is greater than 3 dBm Current Drain 1 Apply 3 0 Vdc to the battery terminals 2 Verify that the current drain is less than 110 mA Preliminary Tests 6 25C1021 BG 25C1021 BG Shure U1 U1L Body Pack UHF Transmitter Frequency Response If the U1 has an attenuator switch on the back of the unit it should be set to 6 dB for the following tests versions G or later Values between board versions may vary slightly the following values are typical values 1 With the transmitter set to minimum gain apply 200 mVrms at 1 kHz to its input Connect the audio analyzer s input to the unbalanced output of the U4 receiver Make sure the receiver volume control is set to maximum With respect to the 1 kHz level measure 8 22 dBu 2 dB Change the frequency to 100 Hz Verify that the measurement from th
21. ed for the center of the frequency range 19 Bench Checks Shure U1 U1L Body Pack UHF Transmitter Low Rf Output Power 2 Check the VCO power output If the power output is still low the VCO is faulty z Verify power across C261 Isolate the rest of the circuit by removing L209 z Check R254 R255 R256 R257 C261 L209 and C248 z Verify the dc bias of Q208 Verify that the rf mute signal changes from 5 V at power on off to 0 V during normal operation If Q209 is not saturated during normal operation rf power at the antenna will be attenuated by approximately 45 dB z lsolate components starting from the antenna and working back to the rf power amplifier 2 Check continuity from U207 pin 1 to the center conductor of J3 z Remove microwave isolator U207 and check the low pass filter power output at LP201 pin 4 It should be approximately 10 dBm z Remove the low pass filter and check the power output of the amplifier at LP206 pin 1 2 Check the output matching network Q208 C258 L206 and C256 2 Check the bypass capacitors C254 C253 C252 and C5 z Replace Q208 z Reinstall L209 and U207 2 Check continuity between pins 1 and 4 of LP201 Excessive Current Drain 2 lsolate different sections of the circuit rf audio digital dc to dc converter z Apply 3 V to the battery terminals and measure the current drain using a dc milliammeter It should be less than 110 mA Dev
22. els shipped after February 1999 have a soldered attached antenna to replace the BELT CLIP 7 screw on removable antenna 8 amp Figure 3 U1 U1L Hand Held Transmitter Disassembly 25C1021 BG 9 Disassembly and Assembly Shure U1 U1L Body Pack UHF Transmitter Reassembly After completing all repairs replace the antenna Then place the circuit boards back in the case making sure the multi pin connectors on the boards mate Reassemble the transmitter by performing the steps of the disassembly procedure in reverse order Disassembly and Assembly 10 25C1021 BG Shure U1 U1L Body Pack UHF Transmitter Service Procedures Service Notes Units With Date Codes Earlier Than August 1996 A small number of synthesizer ICs U204 can experience start up problems with the 4 MHz crystal reference oscillator The problem will only occur for certain values of tuning capacitance The transmitter displays the correct group and channel information However the carrier will have moved to its lowest possible frequency around 750 MHz The tuning voltage of the VCO will read 0 Vdc Adjusting the crystal s tuning capacitor to its lowest value should cause the 4 MHz crystal oscillator to start up and the carrier will lock to the proper frequency The tuning capacitor can now be readjusted to center the carrier to within 1000 kHz However once the unit is turned off the problem may return All units with August 1996 date codes o
23. equency control pin of synthesizer U204 The synthesizer s internal circuitry divides the signal as necessary to reach the desired reference frequency The synthesizer contains a quartz controlled reference oscillator circuit including a 4 0 MHz crystal Y201 that is adjusted by means of trimmer capacitor C239 The transmitter output frequency is user selectable Frequency selection is made via microprocessor U103 which interfaces with the user by means of the mode select switches The output of the synthesiz er is a series of pulses that are integrated by a passive loop filter R238 C245 R240 C266 C267 R239 and C247 to produce a control voltage signal The control voltage signal is then connected to the VCO through amplifier U210A which is used to isolate the PLL filter from the audio modulation signals The VCO output is also coupled to an rf power amplifier through a resistive pad consisting of R254 R255 R256 R257 and an LC match ing network containing C261 L209 and C248 The rf power amplifier dual gate MESFET Q208 is fixed tuned and configured as a common source device Amplifier stability is obtained through resistive loading on the input R247 The output of Q208 contains a low pass matching network L206 and an LC type low pass filter LP206 which provide a high degree of spectral purity The output of the low pass filter feeds a microwave isola tor that reduces the production of reverse third order intermodulat
24. iation Problems z lf R243 cannot be adjusted to obtain 45 kHz deviation isolate the problem to either the audio or rf section s Check R243 2 Check the rf section by setting the transmitter frequency to 800 MHz and verifying that the tuning voltage of the VCO is approximately 3 Vdc Bench Checks 20 25C1021 BG Shure U1 U1L Body Pack UHF Transmitter Replacement Parts and Drawings Model Variations Different frequency versions of the U1 and U1L transmitters are currently available for use in various countries Each version is identified in the table below by country code frequency range and printed circuit board version Some frequency versions have been discontinued For the new list of frequency variations use the MK2 manual Table 2 U1 U1L Model Variations COUNTRY FREQUENCY U1 U1L CODE RANGE DESIGNATION RF AUDIO RF AUDIO PC BOARD NUMBER PC BOARD NUMBER UA MA 782 810 MHz Germany 90MA8739M 90MA8740M ee OSa ating vain puo Longor a JB 806 810 MHz Japan 90JB8739J INNEN vE D WC UNES EA D 800 830 MHz 90MB8739J 774 782 MHz Netherlands 90MC8739J M To create an MD board order the 90MB8739J PCB s and install the MD EEPROM UB 692 716 MHz 90UB8739M 90UB8740M For PCB s that are no longer available use the U1 MK2 manual for replacements Parts Designations The following comments apply to the parts list and the schematic Resistors Unless otherwise noted all resistors are surfac
25. ion products The transmitter is capable of delivering a maximum of 10 dBm 10 mW to the 50 Q antenna During transmitter power up and frequency selection rf power is muted by bringing the base of Q209 high This pro vides approximately 45 dB rf attenuation until the PLL has locked The transmitter rf is then unmuted by bringing the base of Q209 low During transmitter power off conditions voltage is first removed from the VCO by bringing the base of Q207 high In this way the transmitter carrier signal is not allowed to drift off frequency during power on or power off conditions 3 Circuit Description Shure U1 U1L Body Pack UHF Transmitter Transmitter Display Board The display board consists of the following circuitry blocks Microcontroller Section The microcontroller section consists of microcontroller U103 and the liquid crystal display LCD The microcontroller has an on board liquid crystal display LCD driver R111 R113 and R114 supply the microcon troller with the LCD drive voltage for a four plex drive The LCD indicates the UHF frequency group and channel The LCD also has a battery fuel gauge A 4 000 MHz oscillator Y101 provides the operating frequency to the microcontroller The oscillator circuit includes C107 C108 R102 and R103 which along with Y101 U106 R112 and C112 form the reset cir cuit U106 is the reset integrated circuit IC that resets the U103 micro controller if the 5 V normal operating vo
26. ltage falls below 3 5 V R107 is the pull up resistor for the U103 programming voltage pin Memory Section The memory section consists of U101 a non volatile EEPRAM that stores current transmitter settings and the mapping of compatible groups and channels Battery Management Section The battery management section consists of comparator U102 It is used to measure the effective battery voltage with reference to 5 V by measuring the time used to charge a capacitor to a reference threshold of 0 1 Vdc 0 01 Vdc The battery is checked approximately every 5 seconds Comparator U102 alternately charges C106 with 5 V refer ence voltage then the battery voltage PLUS signal test point 1109 User Interface Section The user interface section consists of the Power Mode and Set switches The status of each switch function is indicated on the LCD Power Supply Section The U105 dc to dc converter provides the transmitter with regulated 5 V derived from two AA batteries Power MOSFET Q101 provides reverse battery protection Q103 R118 R286 and C124 control the soft start and reset of dc to dc converter following battery voltage drops Circuit Description 4 25C1021 BG Shure U1 U1L Body Pack UHF Transmitter Preliminary Tests Test Component Locations DDD ls z CBA J104
27. n the 500 SMC connector on PCB versions G and earlier or through the P1824 test cable on PCB versions H and later For JB models with SMT rf test connector use PT1838 AF with PT1838 AJ Rf Alignment 1 Slide the ON OFF switch S103 to the ON position 2 Connect the transmitter to the frequency counter via J3 3 Determine the transmitter operating frequency by comparing the Group and Channel information on the LCD to the tables in the User Guide and User s Guide Supplements 4 Adjust variable capacitor C239 until the frequency counter mea surement matches the desired operating frequency 1 kHz Service Procedures 14 25C1021 BG Shure U1 U1L Body Pack UHF Transmitter Power Output Measurement The output power measurement ensures that the output signal is strong enough for sufficient range when the system is in use The output power measurement also verifies that the output power is not above the specified maximum level to ensure compliance with regulatory agencies standards SPECTRUM ANALYZER ooo 0 DU 0 00g go LJ des J104 J200 C239 gt U202 aa 0 0 oo 0 oooo 00 00 U1 Transmitter Spectrum Analyzer Power ON Peak search ON Signal track ON Marker ON
28. o wires also lead to the battery connector and a three wire flat cable that connects the pcbs to the microphone jack Handle the pcbs with care to avoid damaging these connections 1 Open the battery compartment cover and remove the batteries Remove the belt clip Remove the two screws from the back of the case Lift the top half of the transmitter case away to expose the pcbs Remove the single screw visible next to the antenna connector oa FF 0oN Use the antenna to gently lift up both pcbs far enough so that the antenna assembly clears the case or remove the top pcb to gain better access to the bottom pcb 7 Remove the antenna by unscrewing it from the connector Make sure that the washer on the antenna clears the case 8 Install the new antenna by screwing it onto the connector If necessary replace the conductive rubber gasket at the base of the antenna 9 Return the pcbs to their original position 10 Reinstall the single screw next to the antenna connector 11 Perform these steps in reverse order to reassemble the unit Service Procedures 12 25C1021 BG Shure U1 U1L Body Pack UHF Transmitter Measurement Reference dBu is a measure of voltage and dBm is a measure of power For example the HP8903 should be labeled dBu instead of dBm because it is a voltage measurement These two terms are often used interchangeably even though they have different meanings Audio levels in dBu are marked as dBm on the HP890
29. ower 3 Vdc Measurement AC level Gain Minimum for JB models Output 1 kHz set to MAX Filters Low Pass 30 kHz ON High Pass 400 Hz ON Figure 8 Deviation Reference Voltage Adjustment Test Set Up 1 The U1 transmitter should be turned ON for this procedure 2 Turn the rf signal generator OFF for this procedure 3 For G and later board versions adjust the audio analyzer for 1 kHz to get a level of 5 0 dBu 436 mV at pin 7 of U201 4 ForF or earlier board versions adjust the audio analyzer for 1 kHz to get a level of 5 0 dBu 436 mV at pin 1 of U201 5 On JB models adjust the audio analyzer for 1 kHz to 61 0 dBu at the input connector 6 Connect the transmitter rf output to a U4 antenna connector through a dc block and a 20 dB pad 7 Connect the U4 unbalanced output to the audio analyzer s input 8 Adjust R243 until the audio analyzer reads the deviation reference voltage measured in the last test from the unbalanced output of the U4 receiver 0 1 dB 9 Turn OFF the 30 kHz low pass filter and the 400 Hz high pass filer on the audio analyzer 10 Disconnect the audio analyzer output from the U1 mic input 25C1021 BG 17 Service Procedures Shure U1 U1L Body Pack UHF Transmitter Tone Key Level Adjustment
30. p 56G8069 R201 Potentiometer 0 1 W 20 100 k 46C8049 101 102 Switch pushbutton SPST 55A187 Y202 Crystal 32 768 kHz 40A8010 SMT Components C239 Capacitor trim 7 50 pF 152H02 J200 Header 11 Position 170A07 L101 102 103 Inductor 1596 33 uH 162B16 L104 Resistor 1 8 W 596 0 145AJ000 L201 203 Inductor 1096 0 18 uH 162R10 L202 Ferrite bead 162A03 L206 Inductor 1096 0 12 uH 162A10 LP206 Filter low pass 162A17 Q101 Transistor MOS FET MDT3055EL 183A35 Q201 Transistor NPN SOT 23 MMBT5089L 183A38 Q203 Transistor PNP SOT 23 MMBT5087 183A01 R208 Resistor 1 10 W 1 5 249 145BF2490 R224 243 Trimming pot 1 4 W 2596 1 k 146B02 U104 Diode switching 7000L 184A08 U201 202 Integrated Circuit 33178 188A18 U203 Compander integrated circuit NE575 188A126 U204 PLL Frequency Synthesizer 188A134 Y101 Crystal 4 MHz for Microcontroller 140A005 Y201 Crystal 4 MHz for U204 140A09 25C1021 BG 23 Replacement Parts and Drawings Shure U1 U1L Body Pack UHF Transmitter Table 5 Printed Circuit Board Replacement Parts Side 2 Reference Shure Part Designation Description Number Non SMT Components D102 LED green 86C8419 J2 Receptacle TINI QG 4 pin male Ut ONLY 95A8413 J103 Receptacle LEMO OS U1L ONLY 95A8601 103 Switch toggle DPDT 55A189 SMT Components D101 103 Rectifier Schottky MBRS140 184A16 D201 202 Diode dual 184A08 J104 Receptacle 170A0
31. r later have a 10 kO resistor from pin 2 of the synthesizer to ground to insure that the internal oscillator will start up for all values of tuning capacitance C239 Safe values for the resistor are from 16 8 to 33 2 kO Product Changes 25C1021 BG Antenna Changes All models shipped after February 1999 have a soldered attached antenna 70A801 7 to replace screw on removable antenna Attenuator Switch SW201 Attenuator switch SW201 has been added to the audio section of the rf audio printed circuit board All products shipped after February 1997 board versions F and later should include this switch Inductor L104 Removal Inductor L104 has been removed for improved electrostatic discharge ESD performance On products shipped after March 1997 L104 was replaced with a jumper On F and later versions of the board the circuit was redesigned and the jumper was removed Shure recommends that any product shipped before March 1997 have L104 removed and replaced with a jumper Comparator U102 Comparator U102 has been changed to prevent an 88 88 display 11 Service Procedures Shure U1 U1L Body Pack UHF Transmitter Antenna Replacement NOTE All models shipped after February 1999 have a soldered attached antenna to replace the screw on removable antenna Do not try to remove and replace the soldered attached antennas The top printed circuit board pcb is connected to the bottom pcb by a multi pin connector Tw
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