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Shure Incorporated
222 Hartrey Avenue
Evanston IL 60202-3696  U.S.A.

UHF Wireless System

E

2000, Shure Incorporated

  Printed in U.S.A.

25–1021–2 (BG)

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

Release

Part Number

Date Code

Original

25A1021

QE

Revision 1

25B1021

SA

Revision 2

25C1021

TD

Revision 3

25C1021

AG

Revision 4

25C1021

BF

Revision 5

25C1021

BG

CHANGES EFFECTIVE JULY 12, 2002

REMOVE

these pages from the 

U1/U1L Service Manual

INSERT

these Revised pages into the 

U1/U1L Service Manual

21 to 25

 21 to 25

Summary of Contents for U1

Page 1: ...te 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 Release Part Number Date Code Original 25A1021 QE Revision 1 25B1021 SA Revision 2 25C1021 TD Revision 3 25C1021 AG Revision 4 25C1021 BF R...

Page 2: ......

Page 3: ...f LED 6 Belt Clip 7 MODE Button 12 13 11 10 O N 5 4 1 6 9 7 2 O FF 1 3 8 8 SET Button 9 Audio Gain Control 10 Battery Cover Release Tabs 11 Battery Compartment Cover 12 Battery Fuel Gauge 13 Battery Compartment NOTE All models shipped after February 1999 have a soldered attached antenna to replace the screw on removable antenna Figure 1 U1 UL Transmitter Controls and Indicators Service Note Shure ...

Page 4: ... 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 switc...

Page 5: ...ith 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 ...

Page 6: ...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 ...

Page 7: ...8H ABCD Digital Display Board Side 1 Digital Display Board Side 2 Shorted with a 0 Ω resistor on F board versions and later Rf Audio Board Side 1 Rf Audio Board Side 2 On F board versions and later On F board versions and later Mic Jack Board LEMO 4 Pin Mic Jack Board TINI Q G 4 Pin Figure 2 Test Component Locations ...

Page 8: ...etup 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 Connect 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 f...

Page 9: ... set to minimum gain apply 200 mVrms at 1 kHz to its input 2 Connect the audio analyzer s input to the unbalanced output of the U4 receiver 3 Make sure the receiver volume control is set to maximum 4 With respect to the 1 kHz level measure 8 22 dBu 2 dB 5 Change the frequency to 100 Hz Verify that the measurement from the U4 unbalanced output is within 2 dB with respect to the 1 kHz level 6 Change...

Page 10: ...Shure U1 U1L Body Pack UHF Transmitter 25C1021 BG 8 Notes Notes This page intentionally left blank ...

Page 11: ...ve 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 BELT CLIP BATTERY NEST ANTENNA RF GROUND SCREW TOP COVER BATTERY COMPARTMENT COVER RF AUDIO CIRCUI...

Page 12: ... Assembly 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 ...

Page 13: ... August 1996 date codes or later have a 10 kΩ 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 kΩ Product Changes Antenna Changes All models shipped after February 1999 have a soldered attached antenna 70A8017 to replace screw on removable antenna Attenu...

Page 14: ... 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 pcbs 5 Remove the single screw visible next to the antenna connector 6 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...

Page 15: ...dapter 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 Frequency counter Hewlett Packard 53181A Rf signal generator Hew...

Page 16: ...ls 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 connection the 50Ω 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...

Page 17: ... to ensure compliance with regulatory agencies standards SPECTRUM ANALYZER U1 Transmitter Spectrum Analyzer Power ON Peak search ON Signal track ON Marker ON Figure 6 U1 Power Output Measurement Test Set Up 1 Rf output power is not adjustable Use RG58 or any other low loss 50 Ω cables for all rf connections 2 Include the insertion loss of the cables and connectors in rf conductive power measuremen...

Page 18: ...r to antenna A or B on a U4 receiver Make sure the dc block is on the rf signal generator 3 Set the rf signal generator to the same frequency as the U1 transmitter 4 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 5 Set the output amplitude of the rf signal generator to 50 dBm 6 Turn the U4 re...

Page 19: ...rocedure 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 For F 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 thro...

Page 20: ... kHz OFF High Pass 400 Hz OFF Figure 9 Tone Key Level Adjustment Test Set Up 1 Use a dc 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 m...

Page 21: ...urated during normal operation nVerify that the battery voltage appears at U105 pin 1 nVerify that the Vds drain to source voltage of Q101 is approxi mately 0 025 V Q101 should be saturated nVerify that the dc to dc converter output is 5 V at pin 8 on U105 Rf Problems nIf the carrier is out of specification by less than 40 kHz and cannot be corrected by adjusting C239 check the values of C239 C238...

Page 22: ... isolator U207 and check the low pass filter power output at LP201 pin 4 It should be approximately 10 dBm nRemove the low pass filter and check the power output of the amplifier at LP206 pin 1 nCheck the output matching network Q208 C258 L206 and C256 nCheck the bypass capacitors C254 C253 C252 and C5 nReplace Q208 nReinstall L209 and U207 nCheck continuity between pins 1 and 4 of LP201 Excessive...

Page 23: ...anada 90UA8739J 90UA8740M MA 782 810 MHz Germany 90MA8739M No Longer Available 90MA8740M No Longer Available JB 806 810 MHz Japan 90JB8739J No Longer Available KK 838 862 MHz United Kingdom 90KK8739M MB 800 830 MHz Europe 90MB8739J MC 774 782 MHz Netherlands 90MC8739J MD To create an MD board order the 90MB8739J PCB s and install the MD EEPROM UB 692 716 MHz U S A 90UB8739M 90UB8740M For PCB s tha...

Page 24: ...s 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 80C8198 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...

Page 25: ...tion 170A07 L101 102 103 Inductor 15 33 µH 162B16 L104 Resistor 1 8 W 5 0 145AJ000 L201 203 Inductor 10 0 18 µH 162R10 L202 Ferrite bead 162A03 L206 Inductor 10 0 12 µH 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 ...

Page 26: ...acle 170A08 L200 205 208 211 Inductor 10 0 18 µH 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 MAX751CSA 188A182 U106 Voltage detector 188B210 U20...

Page 27: ...le 7 VCO Selection Country Code UA205 VCO Range Shure Part Number UA MA MC JB 782 810 MHz 187A10R KK 837 863 MHz 187B10R MB MD 800 830 MHz 187C10R UB 692 716 MHz 187D10R Table 8 Microwave Isolator Selection UA207 Country Code Shure Part Number UA MA MB MC MD JB 187A07 KK 187B07 UB 187C07 ...

Page 28: ...Shure U1 U1L Body Pack UHF Transmitter 25C1021 BG 26 Replacement Parts and Drawings This page intentionally left blank ...

Page 29: ...y Pack UHF Transmitter 27 25C1021 BG Replacement Parts and Drawings SIDE 1 MC68H A BC D SIDE 2 U1 U1L Body Pack Transmitter Digital Display Board Legends and Foils E and Earlier Board Versions Shorted with 0 Ω resistor ...

Page 30: ...Shure U1 U1L Body Pack UHF Transmitter 25C1021 BG 28 Replacement Parts and Drawings U1 U1L Body Pack Transmitter Digital Display Board Legends and Foils F and Later Board Versions ...

Page 31: ...Shure U1 U1L Body Pack UHF Transmitter 29 25C1021 BG Replacement Parts and Drawings SIDE 1 SIDE 2 U1 U1L Body Pack Transmitter RF Audio Printed Circuit Board Legends E and Earlier Board Versions ...

Page 32: ...Shure U1 U1L Body Pack UHF Transmitter 25C1021 BG 30 Replacement Parts and Drawings SIDE 1 SIDE 2 U1 U1L Body Pack Transmitter Rf Audio Printed Circuit Board Legends G and Later Board Versions ...

Page 33: ...dy Pack UHF Transmitter 31 25C1021 BG Replacement Parts and Drawings Mic Jack Printed Circuit Board Legends and Foils LEMO 4 Pin TINI QG 4 Pin Mic Jack Printed Circuit Board Legends and Foils LEMO 4 Pin TINI QG 4 Pin ...

Page 34: ...Shure U1 U1L Body Pack UHF Transmitter 25C1021 BG 32 Replacement Parts and Drawings Notes This page intentionally left blank ...

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