Shure Brothers Incorporated 222 Hartrey Avenue Evanston IL 60202-3696 U.S.A. UHF Wireless System SERVICE MANUAL CHANGE NOTICE UHF WIRELESS RECEIVER MODEL U4D Changes and corrections have been made to the Service Manual for the U4D UHF Wireless Receiver. These changes will make it easier to properly align the receivers. To update your Service Manual, remove the pages identified in the tables below and replace them with the pages attached to this Change Notice.
Service Manual 25D1062 (AG) U4D Dual Diversity UHF Receiver General Characteristics The Shure Model U4D Dual Diversity UHF Receiver is a microprocessor controlled dual diversity receiver operating in the UHF frequency range. This product is intended for use in high-end installed sound, rental, and concert sound markets. Different frequency variations are available in various countries. Controls and Connectors 1 2 3 13 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
Shure U4D Dual Diversity UHF Receiver Circuit Description Power Section The receiver accepts power line voltage ranging from 85 Vac to 264 Vac. The receiver hardware uses the +5 Vdc, +12 Vdc and 12 Vdc voltages from the switching power supply. The switching power supply has 40 W overall output power capability, with maximum current capabilities of 4A at 5V, 2A at +12V, and .5A at –12V. It also includes a fast–acting 2.5A fuse.
Shure U4D Dual Diversity UHF Receiver ond mixer. The second down–converter also incorporates an internal IF amplifier that is used with external 10.7 MHz ceramic filters. The 10.7 MHz signal goes to the second IF gain block with detector. The audio output is buffered with an operational amplifier, then processed as described in the Audio section. The noise output is also amplified by the operational amplifier, providing a signal for the noise squelch circuitry.
Shure U4D Dual Diversity UHF Receiver compared to an adjustable squelch level (a dc level). If either channel’s noise is greater than the squelch threshold, its switch is shut off. The outputs from the analog switches are connected at the audio combining stage. This is a unity gain buffer stage where the audio from channel A is combined with the audio from channel B. The output from this stage splits into three paths. The first path goes to a high Q tone key detection circuit.
Shure U4D Dual Diversity UHF Receiver the LEDs. The output from this stage drives the audio level meter on the front panel board. A dc voltage from the detector chip RSSI drives the bar graph integrated circuit on the front board for the rf level meters. Display Board / Digital Section Microcontroller Section The microcontroller section consists of microcontroller U103 and the liquid crystal display (LCD). The microcontroller has an on-board LCD driver.
Shure U4D Dual Diversity UHF Receiver User Interface Section The user interface section consists of switches SW101 MENU, SW103 SELECT, SW102 UP (+), and SW104 DOWN (–). These switches provide access to various user-programmable menus on the front panel display. The LCD provides the user with feedback for all switch actions performed. Audio Output Level Control R110 The audio output level control potentiometer has no associated circuitry in this section. Refer to the Audio Section.
Shure U4D Dual Diversity UHF Receiver Display Board Interconnect with Rf-Audio Board Integrated ribbon cable connector P102 interfaces with the rf-audio board and the networking Interface board through the display board. Pin assignments for the P102 connector are presented in the table below. Table 1 P102 Interconnect Pin Assignments PIN NO.
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Shure U4D Dual Diversity UHF Receiver Preliminary Tests Test Component Locations Rf-Audio Board, Side 1 Preliminary Tests 9 25D1062 (AG)
Shure U4D Dual Diversity UHF Receiver Audio-Rf Board, Side 2 25D1062 (AG) 10 Preliminary Tests
Shure U4D Dual Diversity UHF Receiver Listening Test Before completely disassembling the receiver, operate it to determine whether it is functioning normally and try duplicating the reported malfunction. Refer to the User Guide for operating instructions, troubleshooting suggestions, 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.
Shure U4D Dual Diversity UHF Receiver 8. Make sure the tone key switch (S201) on the receiver rf-audio board is in the ON position.The receiver should be muted. No audio output should be present at the balanced and unbalanced outputs. 9. Slide the tone key switch to the OFF position. J211 can be accessed from the outside of the receiver and is marked BALANCED LOW Z.
Shure U4D Dual Diversity UHF Receiver Disassembly and Assembly ! IMPORTANT SAFETY INSTRUCTIONS ! 1.. 2.. 3.. 4.. 5.. 6.. 7.. 8.. 9.. READ these instructions. KEEP these instructions. HEED all warnings. FOLLOW all instructions. DO NOT use this apparatus near water. CLEAN ONLY with a damp cloth. DO NOT block any of the ventilation openings. Install in accordance with the manufacturer’s instructions. DO NOT defeat the safety purpose of the grounding-type plug. The third prong is provided for your safety.
Shure U4D Dual Diversity UHF Receiver Front Panel Removal 1. Remove the three screws securing the brace and the rf shielding gaskets to the chassis, then remove the brace. 2. Remove the hexnuts and star washers securing the front panel to the inside of the front chassis. 3. Tag and disconnect the power on/off switch from the power supply wires. 4. Remove the rubber monitor volume control knob and the master volume control knob by pulling them away from the front panel. 5.
Shure U4D Dual Diversity UHF Receiver Printed Circuit Board (PCB) Removal Rf-Audio Board Removal 1. Tag and disconnect the cables attached to the pcbs. Standard cable connections are shown in Figure 3. 2. Remove the screws and washers that secure the rf-audio pcb to the receiver chassis, then lift the board out. Display Board Removal 1. Remove the rf shield brace inside the receiver by removing the three screws and washers securing it to the bottom of the chassis. 2.
Shure U4D Dual Diversity UHF Receiver NETWORK INTERFACE BOX ANTENNA B ANTENNA A J203 J216 J203 RECEIVER 1 NETWORK BOARD AC POWER INPUT J216 RECEIVER 2 DC POWER SUPPLY TO MONITOR BOARD TO NET BOARD TO NET TO MONITOR BOARD BOARD TO DISPLAY BOARD TO DISPLAY BOARD RF-AUDIO BOARD RF-AUDIO BOARD SINGLE: BNC REAR J301 J304 J301 J302 J303 DUAL: BNC REAR J303 DUAL: RF/LO DISPLAY BOARD Figure 3.
Shure U4D Dual Diversity UHF Receiver Service Procedures Product Changes The following changes have been made to the U4D receiver. New Volume Control Knobs and Potentiometers The new potentiometers cannot be used on old boards, and the new knob assembly cannot be used with old potentiometers. PRINTED CIRCUIT BOARD REVISION “G” or earlier “H” or later R110 VOLUME CONTROL POTENTIOMETER PART NO. 46A8048 46A8069 VOLUME CONTROL KNOB ASSEMBLY PART NO.
Shure U4D Dual Diversity UHF Receiver 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.
Shure U4D Dual Diversity UHF Receiver Alignment Align Receivers 1 and 2 separately. Receiver 1 is on the left and Receiver 2 is on the right when looking at the front panel. Equipment setup for the alignment procedure is sequential. Test Setup 1. Remove the top cover from the U4D receiver. 2. To reduce the risk of electrical shock, do not touch or short any components in the receiver switching power supply. The heat sink on the power supply and all ac wiring contains hazardous voltages. 3.
Shure U4D Dual Diversity UHF Receiver Alignment 1. Turn the U4D receiver power ON. 2. Connect the U4D receiver antennas. 3. Program the U4D receiver to any clean frequency in the area, using the SET FREQ menu on the display. To do this, select a television channel that is inactive in the area, and then scan for a frequency at which the yellow rf LEDs are not lit. Note this frequency as Fo. 4. Remove the U4D receiver antennas. 5.
Shure U4D Dual Diversity UHF Receiver Rf Tuning, Channel A Dc Voltage Verification DC VOLTMETER DC VOLTMETER ANTENNA A IN ANTENNA B IN S201 S201 (OFF) (OFF) C242 C227 P202 P203 P203 P202 P202 P202 J302 Figure 5. Dc Voltage Level Verification 1. Measure the dc voltage between the center pin of BNC connector ANTENNA A IN, located on the receiver rear panel, and ground. The voltage should measure 12.0 ± 0.5 Vdc. 2.
Shure U4D Dual Diversity UHF Receiver Local Oscillator Frequency Alignment (Channel A) ANTENNA A IN ANTENNA B IN S201 S201 (OFF) (OFF) P202 P203 P202 P203 P202 P202 VC101 U308 VCO TPRF6 PIN 1 J302 FREQUENCY COUNTER CH 2 CH 1 Figure 6. Local Oscillator Frequency Alignment If using a spectrum analyzer, adjust the span so that the frequency accuracy measurement is better than1 kHz. 1. Attach a spectrum analyzer or frequency counter to TPRF6 (pin 1 of the U308 VCO). 2.
Shure U4D Dual Diversity UHF Receiver FM Detector Quadrature Coil Alignment (Channel A) RF SIGNAL GENERATOR NOTE: DC VOLTAGES ARE PRESENT AT MOST RF TEST POINTS. USE A DC BLOCK ON THE RF SIGNAL GENERATOR TO PROTECT TEST EQUIPMENT. DC BLOCK ANTENNA A IN ANTENNA B IN S201 S201 (OFF) (OFF) P202 P203 P202 P203 P202 P202 TP306 U305 L310 for PCB 34A8507 FL311 for PCB 34A8703 AUDIO ANALYZER J302 Figure 7. FM Detector Quadrature Coil Alignment Connections 1.
Shure U4D Dual Diversity UHF Receiver Second Mixer Coil Alignment (Channel A) RF SIGNAL GENERATOR NOTE: DC VOLTAGES ARE PRESENT AT MOST RF TEST POINTS. USE A DC BLOCK ON THE RF SIGNAL GENERATOR TO PROTECT TEST EQUIPMENT. DC BLOCK ANTENNA A IN DC VOLTMETER ANTENNA B IN S201 S201 (OFF) (OFF) P202 P203 P202 P203 P202 P202 U303 / U315 PIN 8 / PIN 17 L313 J302 Figure 8. Channel A Second Mixer Coil Alignment 1. Change the rf input level to –105 dBm. 2.
Shure U4D Dual Diversity UHF Receiver THD Verification and RSSI Adjustment (Channel A) RF SIGNAL GENERATOR NOTE: DC VOLTAGES ARE PRESENT AT MOST RF TEST POINTS. USE A DC BLOCK ON THE RF SIGNAL GENERATOR TO PROTECT TEST EQUIPMENT. DC BLOCK ANTENNA A IN ANTENNA B IN S201 S201 (OFF) (OFF) AUDIO ANALYZER P203 P202 P202 P203 P202 P202 TP306 AUDIO CH A L310 for PCB 34A8507 R355 TP328 RSSI CH A DC VOLTMETER L311 for PCB 34A8703 J302 Figure 9. Channel A RSSI Alignment 1.
Shure U4D Dual Diversity UHF Receiver Noise Set-Up (Channel A) The Noise Setup procedure aligns each channel so that for a given signal-to-noise ratio, the respective dc levels match. RF SIGNAL GENERATOR DC VOLTMETER NOTE: DC VOLTAGES ARE PRESENT AT MOST RF TEST POINTS. USE A DC BLOCK ON THE RF SIGNAL GENERATOR TO PROTECT TEST EQUIPMENT. DC BLOCK ANTENNA A IN ANTENNA B IN S201 S201 (OFF) (OFF) C242 C227 P203 R264 P202 P202 P203 P202 P202 J302 Figure 10.
Shure U4D Dual Diversity UHF Receiver FM Detector Quadrature Coil Alignment (Channel B) RF SIGNAL GENERATOR DC BLOCK ANTENNA A IN ANTENNA B IN S201 S201 (OFF) (OFF) P202 P203 P202 P203 P202 P202 TP308 U310 L304 for PCB 34A8507 FL313 for PCB 34A8703 J302 NOTE: DC VOLTAGES ARE PRESENT AT MOST RF TEST POINTS. USE A DC BLOCK ON THE RF SIGNAL GENERATOR TO PROTECT TEST EQUIPMENT. AUDIO ANALYZER Figure 11. Channel B FM Detector Quadrature Coil Alignment 1.
Shure U4D Dual Diversity UHF Receiver Second Mixer Coil Adjustment (Channel B) RF SIGNAL GENERATOR NOTE: DC VOLTAGES ARE PRESENT AT MOST RF TEST POINTS. USE A DC BLOCK ON THE RF SIGNAL GENERATOR TO PROTECT TEST EQUIPMENT. DC BLOCK ANTENNA A IN ANTENNA B IN S201 S201 (OFF) (OFF) P203 DC VOLTMETER P202 P202 P203 P202 P202 U313 / U316 PIN 8 / PIN 17 L324 J302 Figure 12. Channel B Second Mixer Coil Adjustment Connections 1. Change the rf input level to –105 dBm. 2.
Shure U4D Dual Diversity UHF Receiver THD Verification and RSSI Adjustment (Channel B) RF SIGNAL GENERATOR DC BLOCK ANTENNA A IN ANTENNA B IN S201 S201 (OFF) (OFF) DC VOLTMETER P203 P202 P202 P203 P202 P202 TP308 U310 L304 for PCB 34A8507 R367 TP325 FL313 for PCB 34A8703 J302 AUDIO ANALYZER Figure 13. NOTE: DC VOLTAGES ARE PRESENT AT MOST RF TEST POINTS. USE A DC BLOCK ON THE RF SIGNAL GENERATOR TO PROTECT TEST EQUIPMENT. Channel B RSSI Alignment Connections 1.
Shure U4D Dual Diversity UHF Receiver Noise Setup (Channel B) The Noise Setup procedure aligns each Channel so that for a given signal-to-noise ratio, the respective dc levels match. DC VOLTMETER NOTE: DC VOLTAGES ARE PRESENT AT MOST RF TEST POINTS. USE A DC BLOCK ON THE RF SIGNAL GENERATOR TO PROTECT TEST EQUIPMENT. RF SIGNAL GENERATOR DC BLOCK ANTENNA B IN ANTENNA A IN S201 S201 (OFF) C242 (OFF) U202 R265 C239 U203 U211 P203 P202 P203 P202 P202 P202 J302 Figure 14.
Shure U4D Dual Diversity UHF Receiver Audio Level Setup, Channel B RF SIGNAL GENERATOR DC BLOCK ANTENNA A IN AUDIO ANALYZER ANTENNA B IN S201 S201 (OFF) (OFF) U207 PIN 7 P203 P202 R250 P202 P203 P202 P202 NOTE: DC VOLTAGES ARE PRESENT AT MOST RF TEST POINTS. USE A DC BLOCK ON THE RF SIGNAL GENERATOR TO PROTECT TEST EQUIPMENT. J302 Figure 15. Channel B Audio Level Setup Connections For the following test, make sure the tone key switch (S201) is OFF.
Shure U4D Dual Diversity UHF Receiver Audio Level Setup, Channel A ANTENNA A IN RF SIGNAL GENERATOR S201 S201 (OFF) (OFF) DC BLOCK AUDIO ANALYZER ANTENNA B IN U207 PIN 7 P203 P202 R203 P202 P203 P202 P202 NOTE: DC VOLTAGES ARE PRESENT AT MOST RF TEST POINTS. USE A DC BLOCK ON THE RF SIGNAL GENERATOR TO PROTECT TEST EQUIPMENT. J302 Figure 16. Channel A Audio Level Setup Connections For the following test, make sure the tone key switch (S201) is OFF.
Shure U4D Dual Diversity UHF Receiver Tone Key Filter Alignment Reinstall the antennas for the Tone Key Filter Alignment procedure. ANTENNA B IN ANTENNA A IN DC VOLTMETER S201 (ON) S201 (ON) VC102 PIN 8 U208 P203 P202 P202 P203 P202 P202 J302 Figure 17. Tone Key Filter Alignment Connections For the following test, make sure the tone key switch (S201) is ON. 1. Turn the tone key switch (S201) to the ON position. 2. Turn the rf signal generator output OFF. 3. Be sure to reinstall the antennas. 4.
Shure U4D Dual Diversity UHF Receiver U4D Receiver 2 Alignment The Receiver 2 alignment procedure is identical to the Receiver 1 alignment procedure. However, for the Receiver 2 alignment procedure refer to Antenna B alignment procedures each time Antenna A is called out and refer to Antenna A procedures each time Antenna B is called out.
Shure U4D Dual Diversity UHF Receiver Replacement Parts and Drawings U4D Model Variations Different frequency versions of the U4D receiver 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.
Shure U4D Dual Diversity UHF Receiver Table 4 U4D Receiver Replacement Parts Reference Designation Description Shure Part Number A1 Ac ground wire assembly 90A8677 A2 Ac wire assembly (brown) 90A8678 A3 Ac wire assembly (blue) 90B8678 A4 BNC cable assembly (13–inch) 95C8418 A5 BNC cable assembly, mini pin (17 3/4–inch) 95D8418 A6 Cable assembly, mini pin jumper (11 3/4 inch) 95B8277 A7 Cable assembly, mini pin jumper (3 inch) 95F8277 A8 Cable assembly, ribbon cable (12 inch, 5 pin
Shure U4D Dual Diversity UHF Receiver U4D Receiver Replacement Parts (Continued) Reference Designation Description Shure Part Number MP25 Daisy chain power cord 95A8576 MP26 AC ground wire 90A8677 MP27 Standoff 80A8094 MP28 Cover 53B8433 MP29 Antenna UA820A Table 5 Digital Display Printed Circuit Board Replacement Parts, Non-SMT Components, Side 1 Reference Designation Description Shure Part Number J101, 103 Receptacle assembly, 25 position 95A8583 J104 Shrouded header, 2 position
Shure U4D Dual Diversity UHF Receiver Table 8 Network Interface Printed Circuit Board Replacement Parts, Non-SMT Components, Side 1 Reference Designation Description Shure Part Number P201, 202 Header, dual row 95A8660 P203 Header, single row, 5 position 95A8659 Table 9 Monitor Printed Circuit Board Replacement Parts, SMT Components, Side 1 Reference Designation Description Shure Part Number U201, 202, 204, 205, 207 Dual Op Amp 188A18 Table 10 RF–Audio Printed Circuit Board Replacement Pa
Shure U4D Dual Diversity UHF Receiver Table 11 RF–Audio Printed Circuit Board Replacement Parts, SMT Components, Side 1 Reference Designation Description Shure Part Number D201,202, 203, 204, 205, 210 SMD, switching diode 184A08 F300, 301 Polyswitch, SMD fuse 187A05 FL340, 341 Filter, SMD, low-pass 162A17 L201, 202, 203, 204, 205 Ferrite bead, SMD 162A03 L206, 311, 327, 336 Inductor, SMD, 82 nH 162F06 L208, 209 Inductor, SMD, 180 nH 162D06 L300, 301 Inductor, SMD, 22nH 162C06 L301–
Shure U4D Dual Diversity UHF Receiver Table 13 VCO Selection 25D1062 (AG) Country Code UA205 VCO Range Shure Part Number UA MA MC 824–849 MHz 187A04 KK S2 837–863 MHz 187B04 MB MD R2 800–830 MHz 187C04 UB M3 R6 692–716 MHz 187D04 II R3 R7 JB 824–849 MHz 187A04 40 Replacement Parts and Drawings
Shure U4D Dual Diversity UHF Receiver SIDE 1 SIDE 2 Figure 18.
Shure U4D Dual Diversity UHF Receiver Figure 19.
Shure U4D Dual Diversity UHF Receiver SIDE 1 SIDE 2 Figure 20.
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Shure U4 UHF Diversity Receiver U4 Rf-Audio Printed Circuit Board Legend (Side 1) 25D1062 (TL) 45
Shure U4 Diversity UHF Receiver U4 Rf-Audio Printed Circuit Board Legend (Side 2) 25D1062 (TL) 46
