Shure orporated UC2B User Manual UC2 srv

Shure Incorporated UC2 srv

User manual

E1998, Shure Brothers Inc. Printed in U.S.A.25A1044 (RI)Service ManualUC2 Hand-HeldUHF TransmitterCharacteristicsGeneralThe Shure UC2 Hand-Held UHF Transmitter is a microprocessor-controlled microphone transmitter, operating in the 774 to 862 MHz frequency range. The UC2 hand-held transmitter is used in mid-levelinstalled sound, rental, and concert sound applications. Six frequencyrange variations are available.Controls and Connectors1. Mic Cartridge Grille (87 shown)2. Battery Fuel Gauge LEDs3. Power ON/OFF Switch4. Audio Gain Control5. 9 V Battery6. Battery Cup7. Group Selection Rotary Switch8. Channel Selection Rotary SwitchFigure 1. UC2 Controls and Connectors12348756Service Note: Shure recommends that all service procedures beperformed by a Factory-Authorized Service Center or that the product be returned directly to Shure Brothers Inc.
Shure UC2 Hand-Held UHF Transmitter2Characteristics25A1044 (RI)Circuit DescriptionCONTROLPLL CONTROL MCU EEPROM(MEM)PWR. OFF DETECT+5VREG.GROUP CHANNELSYNTH.RF POWER RF MUTE RF MUTEVCOFROMBATT.UNREG. PWR.+5vAUDIO INPWR.HOLDCIRCUITON / OFFSWITCHFETBYPASSTONE KEYCIRCUITΣTONE CONTROLTONE KEYCALL IDBATTERYMGMT.& FUELGAUGEAUDIOOUTLIMITERCONTROL OUTPUTLIMITERCONTROL INPUTMICFigure 2. UC2 Hand-Held Transmitter Circuit Block Diagram32.768 kHz4 MHz4 MHzMB15A02MC68HC705Audio SectionFCC-ApprovedAudio enters L200, an inductor used as an rf choke. The signal is ac coupled through capacitor C200 into a user adjustable gain stage.Resistors R202 and R203 set up a half-supply bias, and R204 sets theinput impedance for the stage.The back-to-back diodes, D201, are used to keep the op-amp fromsnapping to the rail and reverse phasing when the maximum input volt-age range is exceeded.The 30 dB adjustable gain stage is built around U200A. The userexternally controls the gain of this stage. C206, C207, and C208 protect
Shure UC2 Hand-Held UHF TransmitterCharacteristics325A1044 (RI)the amplifier and bias circuits from rf interference. Due to its topology,this stage is unique because it is non-inverting and allows for a gain lessthan unity.Audio then enters a buffer to the pre-emphasis network and the compression stage. R213, R214, and C211 set up two corners for thepre-emphasis network. The pre-emphasis boosts the high frequenciesbefore transmission.This network feeds an NE575 compander, U202, that utilizes an external amplifier, U201B. The compander performs a 2:1 logarithmiccompression of the audio signal. The pre-emphasis network also plays a role in setting the hinge point (0 dB gain) of the compander.From the compressor, the processed audio enters a low-pass filter,U201D, and then a summing amplifier, U201C. The tone key (and for J frequencies, the call ID signal) is added here to the processed audiosignal.Transistors Q208 and Q209, with crystal Y200, form the tone keyoscillator circuit to provide a stable, continuous 32.768 kHz sine wave.Transistor Q210 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 outputonly when the tone key signal is present with the transmitted signal. Ifthe tone key or the transmitter is turned off, the receiver will be muted.The tone key squelch eliminates receiver noise associated with loss of a carrier. Q211 acts as a switch for toggling the tone key MUTE/UNMUTE; it is controlled via the microprocessor.The tone key signal, along with the processed audio signal, is thenfed to a summing amplifier, U201C. R244, at the output of the summingamplifier, helps prevent spurious oscillations from the op-amp. Afterpassing the ac coupling capacitor, C243, the signal is fed to the rf modulevia the rf choke, L207.The battery meter circuit is comprised of U205; LEDs D203, D204,D205; and various resistors. The meter works by comparing a divideddown version of the battery voltage (R250, R251) to two thresholds (set by R252, R253, and R254), and lighting the appropriate LED.A 9 Vdc battery provides power to the audio printed circuit board(pcb), via switch S200. FET Q203 provides electrical reverse batteryprotection by connecting the negative battery terminal to the pcb groundonly when the battery is connected with the correct polarity.The 9 Vdc then enters U203, a low dropout 5 V regulator, whichgives a clean, regulated 5 V supply to run the audio circuitry. The regulator has appropriate bypass capacitors on its input and output.Q201, Q202, Q212, Q213, and their respective resistors, provide power management and timing.
Shure UC2 Hand-Held UHF Transmitter4Characteristics25A1044 (RI)ETSI-ApprovedThis transmitter uses the same pcb as the domestic system, but itrequires a different topology and different parts.A limiter is inserted between the pre-emphasis and the compressorto limit the occupied bandwidth.The buffer after the gain stage, U201A, is now an inverter with pre-emphasis and 20 dB of attenuation. Previously bypassed, the expander side of the NE575 (U202) is now activated and used as a limiter. A sample of the audio is taken from the limiter output, U202, pin 6, and sent to a control circuit that detects signals above a limitingthreshold. The comparator then sends a control signal to U202, pin 5,which clamps the signal.Rf SectionProcessed audio enters R320, an internal potentiometer that is adjusted for 45 kHz deviation (40 kHz for England), 100% modulation,with a 6.8 dBu 1 kHz tone at the output of the compressor. For J fre-quencies, R320 is adjusted for 5 kHz deviation with 1 kHz tone injectedinto the mic input, to give –23.47 dBu at U201, pin 7 (TPA4).The audio is then fed to the tuning voltage pin of the voltage con-trolled oscillator (VCO), which modulates the carrier directly. A phaselocked-loop (PLL) frequency-synthesized system eliminates the need formultiplier stages and results in a much higher degree of spectral purity.The VCO is shielded to prevent external rf fields from affecting itsoperation. Regulated 5 Vdc power from the low drop-out regulator,U311, is provided to ensure frequency stability with changes in batteryvoltage.The VCO is capable of tuning from 782 to 806 MHz (FCC-approved),with a 1 to 4 V tuning voltage range. At the output of the VCO, the rf signal splits into two paths. Frequency variations by country are givenin a table in the Service Procedures section.The output of the VCO is coupled by C323 to the frequency controlpin of the synthesizer, U304. The synthesizer’s internal circuitry dividesthe rf signal down, as necessary. The synthesizer contains a quartz-con-trolled reference oscillator circuit operating from a 4.0 MHz crystal, Y302,that is adjusted by trimmer C314.The transmitter output frequency is user-selectable in groups of compatible channels from 782 to 806 MHz for domestic groups. Fre-quency selection is made via microprocessor U303, which interfaces withthe user by means of the Group/Channel switches, S301 and S302.The output of the synthesizer is a series of pulses integrated by apassive loop filter (R316, C319, R317, C353, R318, C320) to produce acontrol voltage signal. The control voltage signal is then connected tothe VCO through buffer amplifier U306B, which is used to isolate the PLLfilter from the audio modulation signals.
Shure UC2 Hand-Held UHF TransmitterCharacteristics525A1044 (RI)The VCO output is also coupled to the pre-driver and rf power amplifier through a resistive network (R322, R324, R325) and a coupling capacitor, C329.The pre-driver stage, Q302, provides approximately 6 to 8 dB ofgain, which makes up for the pad. R326 and R327 provide base bias for the transistor, while R328 sets its operating current.L303 is an rf choke used to provide power to the stage, while L304,C332, C333, C357, and C2 provide filtering/matching for the stage. The collector of Q302 feeds into the power amplifier stage via coupling capacitor C338 and a pi-matching network made up of C339, L305, and C340.The rf power amplifier, Q304, is a dual emitter BJT. This high-gain,high-frequency low-noise device can provide +18 dBm out at its 1 dBcompression point. It is biased via base resistors R331 and R332. Itsoperating current is controlled via emitter resistor R333.L306 acts as a choke, and C349, C350, C355, and C356 provide agood emitter bypass to ground. The amplifier output is matched to low-pass filter U1, via L307. The low-pass filter output couples to the printedcircuit board (pcb) via C347 and L308.The transmitter can deliver +17 dBm (50 mW) maximum to the antenna for domestic frequencies; JA and JB frequency transmitters candeliver +10 dBm maximum to the antenna. During transmitter power-upand frequency selection, the rf power is muted by bringing the gates ofQ303/Q305 low. This provides approximately 45 dB rf attenuation untilthe PLL has locked.The transmitter rf is then unmuted by bringing the gates Q303/Q305high. During transmitter power off conditions, voltage is first removedfrom the VCO by bringing the base of Q301 high. Thus, the carrier signalof the transmitter is not allowed to drift off frequency during power on/offconditions.Digital SectionThe digital section contains several circuitry blocks.Microcontroller SectionThe microcontroller section consists of the U303 microcontroller.The rotary switches indicate the UHF frequency group and channel. A4.000 MHz oscillator provides the operating frequency to the microcon-troller. The oscillator circuit includes C300, C301, and Y301. U5, R306,and C305 form the reset circuit. U5 is the reset IC that resets the U303microcontroller if the 5 Vdc normal operating voltage falls below 4.3 Vdc.C302 and C303 form the power supply bypass filter circuit.
Shure UC2 Hand-Held UHF Transmitter6Characteristics25A1044 (RI)Memory SectionThe memory section consists of U302, a non-volatile, ElectricallyErasable/Programmable Read Only Memory (EEPROM) that stores themapping of the compatible groups and channels. The microcontrollerserially communicates with this part via data and clock lines to read thefrequency corresponding to the Group and Channel position.The ability to write to the memory occurs during factory programmingonly. During normal usage, this memory is used as a look-up table only.R335 and R305 resistors allow the clock and data lines to be drivenindependently of the microcontroller port pin states during in-circuit pro-gramming of the EEPROM.Battery Management SectionThe U303 microcontroller provides low battery shutdown. The shut-down threshold is 1.88 Vdc ± 10%. A voltage lower than the shutdownthreshold on U303, pin 17, shuts down the transmitter. Resistors R308and R309 divide down the battery voltage for U303; a battery voltageless than 5.65 Vdc must shut down the transmitter.This auto shutdown disables the audio tone key mix, mutes the rfoutput, and powers down the rf output amplifier section. The currentdraw from a 9 Vdc battery in this state is 14 ± 2.0 mA, and the batteryfuel gauge is not functional. Turning off the power switch completelyshuts off the transmitter.The audio circuit description section provides information for the battery fuel gauge circuit description.Rotary Switches for Frequency SelectionA 10-position Group switch (S302) and a 16-position Channel switch(S301) select the transmitter frequency. Both rotary switches share thesame U303 microcontroller port pins (3 through 6) for a multiplexedswitch read operation. The individual switches are selected by U303,pins 7 and 8. Resistors R4, R300, R302, and R303 are the pull-ups forthe switch position read. Diode packs D301 through D304 isolate theswitches during the multiplexed read operation.The multiplexed scheme to read switches does not allow incorporat-ing switch change detection based on interrupts. Also, the switches can-not be constantly scanned to determine changes because the scanningfrequency being in audio range is difficult to filter out.In a steady state, the switch selector common pins are inputs to theU303, pins 7 and 8, while U303, pins 3 through 6, are outputs. In thisstate, pins 4, 5, and 6 are held low while pin 3 is held high. This forceslogic high level on switch selector pins if the switches are set on oddpositions. For even position settings, the contact on pin 1 is open fromthe switch common pin and the internal pull-down resistors force logiclow to U303, pins 7 and 8.
Shure UC2 Hand-Held UHF TransmitterCharacteristics725A1044 (RI)Any switch change is comprised of state toggle from odd to even,and vice versa. Only this change is detected, and it is followed by a multiplexed switch read, in which U303, pins 7 and 8, become selectivelygrounded outputs to read the selected switch’s state on pins 3 through 6.A multiplexed switch read is preceded by tone key and rf mutes.This mutes the audio in the receiver to allow a quiet change to anotherfrequency.For JA frequencies, the Group switch has 16 positions, and theChannel switch has 10 positions.Power Switch and Mute InterfaceWhen a transmitter is turned off, the PWRDN signal goes to logic lowon U303, pin 19. This immediately disables the tone key, and the powerhold circuit automatically kicks in to bypass the power switch. This isfollowed by 500 mS of delay, and then the rf is muted and turned off.The power hold circuit is also disabled at this point, and the transmittershuts off.
Shure UC2 Hand-Held UHF Transmitter8Notes25A1044 (RI)NotesThis page intentionally left blank.
Shure UC2 Hand-Held UHF TransmitterFunctional Test925A1044 (RI)Functional TestVerify operation and reported malfunction, referring to the productUser’s Guide for a description of the unit as well as information on its operation, troubleshooting, and technical data.Disassembly and Assembly! CAUTION !Observe precautions when handling this static-sensitive device.Disassembly1. Remove the microphone cartridge from the UC2.2. Use a pair of needlenosed pliers to remove the circuit board retaining ring from inside the handle.3. Push the bezel tab-snap in the handle behind the contact pcb toremove the bezel and switch actuator.4. Slide the circuit board out by pushing on the battery connectors.Right side view of microphoneBezelHandle TabCircuit board subassemblyTabFigure 3. Bezel RemovalContact pcbSwitch actuator
Shure UC2 Hand-Held UHF Transmitter10Disassembly and Assembly25A1044 (RI)Microphonecartridge(SM58 shown)Ball screenContact boardGain controlAudio circuitboardBezelSwitchactuator9 Vdc alkalinebatteryRf circuitboardGain controlaccessBattery cupHandleFigure 4. UC2 Hand-Held Transmitter, exploded view.RetainingringReassemblyTo reassemble the unit, reverse the disassembly steps given above:1. Slide the circuit board back into the handle.2. Reinstall the retaining ring, switch actuator, bezel, and the microphone cartridge.
Shure UC2 Hand-Held UHF TransmitterService Procedures1125A1044 (RI)Service ProceduresMeasurement ReferencedBu 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 usedinterchangeably even though they have different meanings.Audio levels in dBu are marked as dBm on the HP8903.dB Conversion Chart0 dBV =2.2 dBu0 dBu =0 dBm, assuming the load = 600 ΩTest EquipmentMost test equipment needed is described in the Shure Wireless Service Equipment Manual. The following test equipment (or approvedequivalent) is also needed.Table 1Test EquipmentEquipment Type ModelAudio analyzer *Hewlett-Packard 8903BDigital multimeter Fluke 87Rf signal generator Hewlett-Packard 8656BFrequency counter Hewlett-Packard 53181ASpectrum analyzer (domestic) Hewlett-Packard 8590LSpectrum analyzer (JA, JB) Hewlett-Packard 8591EShure UC4 receiver Shure UC4Test head PT1840Brass ring for use with test head PT1838–YBNC to “rocket launch” cable 95C8418–1*Audio levels in dBu are marked as dBm on the HP8903B.Test Equipment Set-UpThe alignment procedure is sequential and does not change,unless specified.1. Use RG58 or any low loss, 50 Ω cables for all rf connections.Use a BNC to “rocket launch” cable for J frequencies.2. Keep the test cables as short as possible.3. Include the insertion loss of the cables and connectors for all rfmeasurements.4. Dc voltages may be present at rf test points. As a precaution,use dc blocks to protect the test equipment
Shure UC2 Hand-Held UHF Transmitter12Service Procedures25A1044 (RI)Test Set-UpU200AUDIO SIDE 1D201C200J205 Q220TP18TP10TP4TP6+5V+9VU201U202C216R7U205Y200S200GND1U203Q203Q202Q204 Q209Q201Q212Q213 C222 C214PADC27C291REDGREENS301S302 RF GND*TPRF1 J2*R40*Q304Y302 C314R320U302U303Y301U501C5101TP30TP+9L302Q301C308U311C309RF SIDE 1AUDIO SIDE 2RF SIDE 2J202J201J302J301C227C251C223C221C210Q211 Q210Q208Q3 Q2U2L1Q1C243L207TP2 TP16TP6TP4TP10C213TP18+9V+5VJ200J300D304D303D302D301U5C303C324U306C353 U304 C315C336Q305Q303L300U1U1 C347L308TPRF1TP30TP+911R39P201P200P203P204L2R25*J2 and R40 are placed for JA, JB frequencies only. RF GND is accessed thru a hole in the pcb.Figure 5. UC2 Major Test Component Locations1. Use the PT1843 cable to connect the audio board to the rf boardthrough the 11-pin board interconnects (J200, J300, side 2).2. Apply + 9 Vdc across the battery terminals (J201, J202, side 2).3. Set the audio GAIN potentiometer (R207, side 1) to minimum, full counter-clockwise (CCW).4. See Table 2 for frequency settings.
Shure UC2 Hand-Held UHF TransmitterService Procedures1325A1044 (RI)Table 2 lists the group carrier frequencies, switch settings,and tuning voltages for all the alignment tests that follow.Table 2Group Carrier Frequencies and Tuning Voltages(in order by carrier frequency)Group GroupCodeGroupSwitch(S101)ChannelSwitch(S102)CarrierFrequency (MHz)VCO TuningVoltage(TP130) Deviation(kHz)UA A 4 0 805.500 3.7 45MB B 1 3 805.500 2.2 15JA C 0 2 805.500 3.7 5JB D 4 2 807.500 3.8 5KK E 5 5 857.125 2.9 15MC – – – – – –
Shure UC2 Hand-Held UHF Transmitter14Service Procedures25A1044 (RI)AlignmentUse this service procedure to correctly align the transmitter’s operating (output) frequency. C510 tunes the voltage-controlled oscillator (VCO) to the operating frequency selected, with a 1 – 4 Vdctuning range.C314 adjusts the reference oscillator on the synthesizer, U304.AUDIO ANALYZERRETAININGRINGTESTHEADFREQUENCY COUNTERJ205J205 S200AUDIO SIDE 1TPRF1 C347RF SIDE 2CH 2CH 1UC2 Transmitter Audio Analyzer Frequency CounterPower (S200): ON (+9 Vdc) Measurement: AC level Operating freq: See Table 2Operating freq: See Table 2 Filters: Connect CH 2: TPRF1 and GNDGain: Minimum Low-Pass (30 kHz): ON For JA,JB frequencies:Connect to J2High-Pass (400 Hz): ONConnect to J2(pcb rf side 1)Figure 6. UC2 Frequency Alignment Set-Up1. Remove C347 and connect a 50 Ω cable between TPRF1 / RF GND and a frequency counter.For JA, JB frequencies, do not remove C347. Connect a“rocket launch” cable between J2 and the frequency counter. J2 is only placed on the JA, JB frequency assemblies.2. Use a PT1840 test head and brass ring (PT1838-Y) to connectthe audio analyzer to the UC2 audio input (J205). Turn ON theLow-Pass (30 kHz) and High-Pass (400 Hz) filters on the audioanalyzer.For bench testing, the audio analyzer can be directly connectedto the contact board gold contacts with clip leads.3. Toggle the power switch, S200, to turn on the UC2 transmitter.4. Set the UC2 Group and Channel switches, S301 and S302, according to the group designators on the board and the settings given in Table 2.
Shure UC2 Hand-Held UHF TransmitterService Procedures1525A1044 (RI)FrequencyUse this service procedure to correctly align the transmitter’s operating (output) frequency. C510 tunes the voltage-controlled oscillator (VCO) to the operating frequency selected, with a 1 – 4 Vdctuning range.C314 adjusts the reference oscillator on the synthesizer, U304.FREQUENCY COUNTERDC VOLTMETER+–CH 2CH 1TP30C510U501C314J2*RFGNDS302REDS301GREEN TPRF1*R40 and J2 are placed for JA, JB frequencies only.RF GND: FEED THRUHOLE ON PCBR40*UC2 Transmitter Frequency Counter DC VoltmeterPower: ON (+9 Vdc) Operating freq: See Table 2 Connect + : TP30Operating freq: See Table 2 Connect CH 2: TPRF1 and GND Connect – : RF GNDChannel switch: See Table 2 For JA,JB frequencies:Connect to J2Group switch: See Table 2Connect to J2(pcb rf side 1)Figure 7. UC2 Frequency Test Set-Up1. Put a dc voltmeter across TP30 (tuning voltage line) and RF GND.2. Adjust the VCO trimmer, C510, until the voltmeter readingmatches the appropriate entry in Table 2, ± 0.125 Vdc.3. Adjust the variable capacitor, C314, until the frequency countermeasurement matches the appropriate frequency in Table 2,± 1 kHz.4. Leave the test cable connected to the rf output.5. Turn the transmitter OFF.6. The dc voltmeter can be removed from TP30.
Shure UC2 Hand-Held UHF Transmitter16Service Procedures25A1044 (RI)Power Output MeasurementThe output power measurement ensures that the output signal isstrong enough for sufficient range when the system is in use. The outputpower measurement also verifies that the output power is not above thespecified maximum level, to ensure compliance with regulatory agenciesstandards.SPECTRUM ANALYZERTP30C510U501C314J2*RFGNDS302REDS301GREEN TPRF1RF GND: FEED THRU HOLE IN PCB*R40 and J2 are placed for JA, JB frequencies only.R40*UC2 Transmitter Spectrum AnalyzerPower: ON Frequency: See Table 2Operating freq: See Table 2 Span: 200 MHzReference voltage: 20 dBmPeak search: ONSignal track: ONMarker: ONFigure 8. UC2 Power Output Measurement Test Set-Up1. Remove the BNC cable end from the frequency counter and connect it to the 50 Ω input of the spectrum analyzer.. Use theequipment settings shown in Figure 8.2. Measure the output power. The output power should be:UA, MB, MC frequencies: 16 + 1 / – 2 dBmKK frequencies: 14 + 1 / – 2 dBm For J frequencies, with C347 in place, adjust R40 to obtain 8.8 ± 0.5 dBm.3. Turn the UC2 power OFF.4. Remove the BNC end of the cable from the spectrum analyzer,but leave the bare end soldered to the printed circuit board (pcb).5. For JA, JB frequencies, leave the “rocket launcher” cable connected.
Shure UC2 Hand-Held UHF TransmitterService Procedures1725A1044 (RI)Deviation Reference Voltage, Using a UC4 or U4S ReceiverDeviation must be set to make sure the companding systems be-tween the transmitter and receiver correctly track each other. The levelcoming out of the transmitter’s audio compressor must match the levelgoing into the receiver’s audio expander. A fixed gain structure does notensure an exact match, primarily because of variations in voltage-controlled oscillators (VCOs).This test requires a UC4 or a U4S receiver and is designed to tunethe transmitter regardless of the accuracy of the receiver’s tuning. It is,however, recommended that a properly-tuned receiver be used to per-form the transmitter deviation adjustment.TK ON TK OFFS501(TONE KEY SWITCH)UC4 RECEIVER (BACK)RF SIGNAL GENERATORAUDIO ANALYZER DC BLOCKUC4 RECEIVER (FRONT)ABSQUELCHNOTE: DC VOLTAGES ARE PRESENT AT MOST RF TEST POINTS. USE A DC BLOCK ON THE RF SIGNALGENERATOR TO PROTECT TEST EQUIPMENT.UC4 Receiver Audio Analyzer Rf Signal GeneratorOutput: Unbalanced Measurement: AC level INT: FMGain: Maximum Filters: INT: 1 kHzSquelch: Mid Low-Pass (30 kHz): ON Output amplitude: –60 dBmTone Key (S501): OFF High-Pass (400 Hz): ON Frequency: See Table 2Group switch: See Table 2 Modulation: See Table 2Channel switch: See Table 2Figure 9. Deviation Reference Voltage Test Set-Up, Using a UC4 or U4S Receiver1. Connect the rf signal generator to one of the receiver’santenna port B.2. Turn the UC4 or U4S receiver ON.3. Set the receiver frequency to match the transmitter frequency.4. Set the rf signal generator frequency to match the transmitterfrequency.5. Modulate the generator frequency with 1 kHz audio at a–60 dBm output level. See Table 2 for deviation.6. Set the tone key switch (S501 for the UC4, S201 for the U4S) to the OFF position.7. Connect the ac voltmeter to the unbalanced output of the receiver.8. Read the ac voltage.Record this voltage. This is the deviation reference voltage.
Shure UC2 Hand-Held UHF Transmitter18Service Procedures25A1044 (RI)Deviation Adjustment Voltage: Using a UC4 or U4S ReceiverAUDIO ANALYZERS501(TONE KEY SWITCH)TPA4 –U201,pin 7AUDIOSIDE 1UC4 Receiver UC2 Transmitter Audio AnalyzerOutput: Unbalanced Power: + 9 Vdc Measurement: AC levelGain: Maximum Gain: Minimum Frequency Output: 1 kHzSquelch: Mid Filters:Tone Key (S501): ON Low-Pass (30 kHz): ONHigh-Pass (400 Hz): ONFigure 10. Deviation Adjustment Voltage Test Set-Up, Using a UC4 or U4S Receiver, Steps 1 through 3Reassemble the printed circuit boards for this test.1. Disconnect the rf signal generator from the UC4 receiver andreturn the UC4 tone key switch to the ON position.2. Connect the audio analyzer output to the MIC input of the transmitter, using the test head or clip leads to the gold springcontacts.3. Adjust the audio input level using the audio analyzer output tomeasure the following at TPA4 (U201, pin 7) :UA MB, MC JA, JB KK–6.8 dBu ± 0.2 dB(354 mV ± 1 mV) – 16.3 dBu(118 mV ± 1 mV) – 23.47 dBu(52 mV ± 1 mV) – 15.3 dBu(133 mV ± 1 mV)See Figure 11 for equipment set-up and equipment settings forsteps 4 through 6.
Shure UC2 Hand-Held UHF TransmitterService Procedures1925A1044 (RI)Deviation Adjustment Voltage: Using a UC4 or U4S ReceiverAUDIO ANALYZERS501(TONE KEY SWITCH)RF SIDE 1R320VCO20 dBUC4 Receiver UC2 Transmitter Audio AnalyzerOutput: Unbalanced Power: + 9 Vdc Measurement: AC levelGain: Maximum Gain: Minimum Frequency Output: 1 kHzSquelch: Mid Filters:Tone key (S501): ON Low-Pass (30 kHz): ONHigh-Pass (400 Hz): ONFigure 11. Deviation Reference Voltage Test Set-Up, Steps 4 through 6, Using a UC4 or U4S Receiver4. Connect the unbalanced output of the UC4 to the input of theaudio analyzer (ac voltmeter).5. Connect the BNC end of the cable from the rf output of the UC2to the antenna input of the UC4 through a 20 dB in line pad.6. Turn the transmitter ON and adjust R320 until the ac voltmeteron the receiver reads the same as the deviation referencevoltage, measured above, ± 0.1 dB; or ± 0.2 dB for JA, JB frequencies..
Shure UC2 Hand-Held UHF Transmitter20Service Procedures25A1044 (RI)Deviation Reference Voltage: Using a Modified SC4 IF Receiver.Deviation tests can also be performed using a modified SC4 IF receiver. For instructions on modifying an SC4 receiver, consult theShure Service Equipment manual.RF SIGNAL GENERATORAUDIO ANALYZERDC BLOCKNOTE: DC VOLTAGES ARE PRESENT AT MOST RF TESTPOINTS. USE A DC BLOCK ON THE RF SIGNAL GENERATOR TO PROTECT TEST EQUIPMENT.RILZAD–1 MIXERMODIFIED SC4 IF RECEIVERANTENNA INPUT B AUDIO OUTTONE KEY SWITCH: OFFSC4 IF Receiver Audio Analyzer Rf Signal GeneratorOutput: Unbalanced Measurement: AC level INT: FMGain: Maximum Filters: INT: 1 kHzSquelch: Mid Low-Pass (30 kHz): ON Output amplitude: + 7 dBmTone Key switch: OFF High-Pass (400 Hz): ON Frequency: 10.7 MHzOperating freq: See Table 2 Modulation: See Table 2Figure 12. Deviation Reference Voltage Test Set-Up, Using a Modified SC4 IF Receiver1. See Figure 12 for equipment test set-up and equipment settings.2. Connect the rf signal generator output to the input port (L) of aZad-1 mixer3. Connect the output port I (intermediate frequency) of the Zad–1mixer to antenna input B of the SC4 IF receiver.4. Turn the SC4 IF receiver ON and set the tone key switch on thefront panel of the SC4 IF receiver to OFF.5. Connect the audio voltmeter to the receiver’s unbalanced output.6. Measure the output voltage.Record this voltage. This is the deviation reference voltage.Use the same Zad-1 mixer connections for the next adjustment test.
Shure UC2 Hand-Held UHF TransmitterService Procedures2125A1044 (RI)Deviation Adjustment Voltage: Using an SC4 IF ReceiverAUDIO ANALYZERTEST HEADAUDIOSIDE 1TPA4(U201, PIN 7)UC2 Transmitter Audio AnalyzerPower: +9 Vdc Measurement: AC levelGain: Minimum Frequency Output: 1 kHzFilters:Low-Pass (30 kHz): ONHigh-Pass (400 Hz): ONFigure 13. Deviation Adjustment Voltage Test Set-Up, Steps 1 through 5, Using a Modified SC4 IF Receiver1. Disconnect the rf signal generator from the SC4 IF receiver.2. Set the SC4 tone key switch on the SC4 front panel to ON.3. Connect the audio analyzer output to the MIC input of the transmitter, using the test head or clip leads to the gold springcontacts.4. Turn the UC2 power back ON.5. Adjust the audio input level using the audio analyzer output tomeasure the following at TPA4 (U201, pin 7) :UA MB, MC JA, JB KK–6.8 dBu ± 0.2 dB(354 mV ± 1 mV) – 16.3 dBu(118 mV ± 1 mV) – 23.47 dBu(52 mV ± 1 mV) – 15.3 dBu(133 mV ± 1 mV)See Figure 14 for equipment set-up and equipment settings for steps 6 through 8.
Shure UC2 Hand-Held UHF Transmitter22Service Procedures25A1044 (RI)Deviation Adjustment Voltage: Using a Modified SC4 IF ReceiverRF SIGNAL GENERATORAUDIO ANALYZERDC BLOCKNOTE: DC VOLTAGES ARE PRESENT AT MOST RF TESTPOINTS. USE A DC BLOCK ON THE RF SIGNAL GENERATOR TO PROTECT TEST EQUIPMENT.TRANSMITTERANTENNAOUTPUT RILZAD–1 MIXERMODIFIED SC4 IF RECEIVERANTENNA INPUT B AUDIO OUTTONE KEY SWITCH: ONAUDIOINSC4 IF Receiver UC2 Transmitter Audio Analyzer Rf Signal GeneratorOutput: Unbalanced Power: + 9 Vdc Measurement: AC level INT: FMGain: Maximum Gain: Minimum Output: 1 kHz INT: 1 kHzSquelch: Mid Filters: Output amplitude: + 7 dBmTone Key switch: ON Low-Pass (30 kHz): ON Modulation: See Table 2High-Pass (400 Hz): ON Frequency: Oper. Freq. minus 10.7MHzFigure 14. Deviation Adjustment Voltage Test Set-Up, Steps 6 through 8, Using a Modified SC4 IF Receiver6. Connect the UC2 rf output test cable BNC end to the input port(R) of the Zad-1 mixer.7. Connect the rf signal generator, and set the frequency to the operating frequency (from Table 2) minus 10.7 MHz.8. Turn ON the UC2 and adjust R320 until the audio voltmeter connected to the unbalanced output of the UC4 reads the sameas the deviation reference voltage, measured above, ± 0.1 dB,or ± 0.2 dB for JA, JB frequencies..
Shure UC2 Hand-Held UHF TransmitterService Procedures2325A1044 (RI)Product SpecificationsAfter tuning, the unit should meet the following specifications.Specification Minimum Typical MaximumCurrent drain 50 mA 60 mA 70 mAFrequency –1.0 kHz See Table 2 +1.0 kHzAudio freq response @ 100 Hz wrt 1 k –5.0 dB –4.0 dB –3.0 dBAudio freq response @ 10 Hz wrt 1 k +8.0 dB +9.0 dB +10.0 dBUA:System S/N @ 45 kHz, A weighted 95.0 dB 100.0 dB –Output power, UA, without C347 14.0 dBm 16.0 dBm 17.0 dBmMB, MCSystem S/N @ 1% THD, A weighted 80.0 dB 85.0 dB –Output power, without C347 14.0 dBm 16.0 dBm 17.0 dBmKK:System S/N @ 1% THD, A weighted 80.0 dB 85.0 dB –Output power, without C347 12.0 dBm 14.0 dBm 15.0 dBmJA, JB:System S/N @ 1% THD, A weighted 85.0 dB 90.0 dB –Output power, at J2, with C347 in place 8.3 dBm 8.8 dBm 9.3 dBm
Shure UC2 Hand-Held UHF Transmitter24Notes25A1044 (RI)NotesThis page intentionally left blank.
Shure UC2 Hand-Held UHF TransmitterBench Checks2525A1044 (RI)Bench ChecksDc ProblemsMake all dc measurements with respect to the rf ground unlessotherwise specified. Connect the rf and audio printed circuit boards together via the 11 pin connector, the battery contacts, and the “D” board.nMake sure the battery voltage is between 6 and 9 Vdc. Makesure TP+9 has this voltage. Check for the correct Vcc and +5 Vrf at Q301.If incorrect voltage is present:nTrace the dc back to the voltage regulator.nCheck the biasing resistor values around Q301.nCheck the power switch.nLook for open coils, cracked parts, reversed polarity capacitors,or solder shorts. If there is a short to ground from 5 V, try to isolate different parts of the circuit.Make sure that:nThe rf OFF signal changes from +5 Vdc at power up and powerdown to 0 Vdc during normal operation. Trace the signal to the microprocessor. Q301 should be saturated during normal operation.nBattery voltage appears at TP+9, U311, pin 6. Check for reversed polarity capacitors, C308 and C309. Check for opencoil, L300.Rf ProblemsnIf the carrier is out of specification by less than 40 kHz and can-not be corrected by adjusting C314, put the transmitter on theoperating frequency (see Table 2). Measure and adjust the dcvoltage at TP30. (See Table 2 for frequency variations.) If thecarrier still cannot be trimmed properly, then check C314, C313,and Y302. If they are correct, replace the synthesizer.If the carrier frequency is not in the correct frequency range shown inTable 2, or is unstable, the loop is unlocked.nCheck dc voltage at TP30. If it is 0 V or +5 V, look for a short.nCheck the solder connections at the contact board, VCO, microprocessor (traces LE, D, and CK), and synthesizer U304. If theconnections are good and there is no 4.0 MHz oscillation atU304, pins 1 and 2, replace the crystal, Y302.nCheck the values and polarity of the loop filter: R316, C319,R317, C353, R318, C320, C354, U306B, R319, R320, andR321. Check the bias voltage of U304, pins 3 and 4, andU306B, pin 8. As a last resort, replace the synthesizer, U304.
Shure UC2 Hand-Held UHF Transmitter26Bench Checks25A1044 (RI)Low Rf Output PowernCheck the polarity/soldering of the output low-pass filter, U1. (Rf IN is marked with a dot.)nCheck for opens or shorts on output coil L308.nCheck the polarity of Q304.nVerify the dc bias of Q302 and Q304. Check L303, L304, andL306, if no bias. Verify that the rf MUTE signal changes from 0 Vdc at power up and power down to +5 Vdc during normal operation. If Q303 and Q305 are not in a low impedance stateduring normal operation, the rf power at the antenna port will beattenuated by about 45 dB.nCheck for missing ground connections.nCheck the dc level at the VCO Vcc pin. If no dc power, check L302.nVerify the VCO output power.nPartially isolate the VCO from the rest of the circuit by removingC323. The carrier frequency will no longer be locked, but theoutput power from the VCO should be around –1 ± 2 dBm into a 50 Ω load.nIf the power out of the VCO is still low, the problem is in the VCO.nCheck the values of R322, R323, R324, R325, and C329.nIsolate components starting from the antenna and working backto the rf power amp.nCheck the values/continuity of the input and output matching net-works for Q302, Q304 (C329, C338, L305, C339, C340, L307).nCheck the values of the bypass capacitors C357, C2, C332,C333, C334, C335, C360, C341, C342, C349, C350, C355,C356.nAs a last resort, replace Q302 or Q304.Excessive Current DrainnTry isolating different sections of the circuit: rf, audio, digital.Look for reversed polarity capacitors or wrong resistor values.Check the voltage regulators.Deviation ProblemsnIf R320 cannot be adjusted to obtain the deviation reference voltage (see the Service Procedures section), try to isolate theproblem to the audio or rf section. Check the value of R320. Tocheck the rf section, set the transmitter frequency (see Table 2),and verify the tuning voltage of the VCO.nCheck the audio section by applying audio to the mic input. Withan oscilloscope, make sure audio is present at TPA7. If not,work backwards towards the input.
Shure UC2 Hand-Held UHF TransmitterBench Checks2725A1044 (RI)Audio ProblemsNo Tone KeyNo tone key means that the 32.768 kHz tone key sidebands are not visible when the carrier is viewed on a spectrum analyzer. If tone keylevels are there but are too low, the deviation is off and needs to be recalibrated. They should be, roughly, –23 dBc ± 3 dB.nApply a 1 kHz tone at a level of 0 dBu to the audio input with theaudio gain pot at minimum.nIf the carrier on the spectrum analyzer does not show any devi-ation, check part integrity and audio path continuity betweenU201, pin 14, and the VCO.nIf the spectrum analyzer shows a deviated carrier, probe for a 32 kHz signal at TPA6 and I209 and continue to the next step.nIf there is a signal at I209 but not at TPA6, then the mute circuitthrough Q211 is being activated. Verify that the logic signal atQ211, pin 1, is logic low. If it is low, replace Q211. If it is not low,check the line for a short to +5 V. If there is no short, the micro-processor is defective and must be replaced.nIf there is a 32 kHz signal at both I209 and TPA6, replace R236.nIf there is not a 32 kHz signal at either I209 or TPA6, there issomething wrong with the tone key circuit or the tone key supplyvoltage. If the tone key supply voltage (U200, pin 8) is less than2 V, there is a problem with one or more of the following com-ponents: R261, R264, R265, R266, C238, Q220, C237, R232,or R260.nIf the voltage at U200, pin 8, is greater than 2 V, the problem is inthe tone key circuit itself. Check for shorts and opens. Replaceparts in this circuit beginning with the crystal until the 32 kHz oscillation returns.No AudionView the carrier on the spectrum analyzer. If there are not 32 kHz tone key sidebands around the carrier, follow the stepsabove for “No Tone Key.”nVerify +9 V, half-supply bias, and ground connections to U200.nVerify +9 V, half-supply bias, and ground connections to U201.nFollow the audio path from where audio is applied until the pointof discontinuity is reached and replace the appropriate part.
Shure UC2 Hand-Held UHF Transmitter28Notes25A1044 (RI)NotesThis page intentionally left blank.
Shure UC2 Hand-Held UHF TransmitterReplacement Parts and Drawings2925A1044 (RI)Replacement Parts and DrawingsParts DesignationsThe following comments apply to the parts list and the schematic:Resistors: Unless otherwise noted, all resistors are surface-mount0603 size, with 1/10 W rating and 1% tolerance.Capacitors: Unless otherwise noted, non-polarized capacitors aresurface-mount NPO dielectric types with a 100 V capacity and a 5% tolerance, and polarized capacitors are tantalum types.Table 3UC2 Model Frequency VariationsPrinted Circuit Boards(in order by frequency)CountryCode CountryDesignation Frequency Range UC2 PrintedCircuit Board #MC Netherlands 774 – 782 MHz 90MC8792JUA U.S.A. and Canada 782 – 806 MHz 90UA8792JJA Japan 797 – 806 MHz 90JA8792JMB Europe 800 – 830 MHz 90MB8792JJB Japan 806 – 810 MHz 90JB8792JKK United Kingdom 838 – 862 MHz 90KK8792JTable 4Replacement PartsReferenceDesignation Description Shure PartNumberMP1 Actuator 65B8298MP2 Battery snap (positive) 56A317MP3 Battery snap (negative) 56A318MP4 Bezel 65A8299MP5 Compression disc (in battery cup) 38A180MP6 Contact (on contact pcb) 53D2039MP7 Cup 65A8300AMP8 Handle 65A8301AMP9 Interconnect strip 56D8074MP9 Nameplate, bottom 39–8302MP10 Nameplate, handle 39–8303
Shure UC2 Hand-Held UHF Transmitter30Replacement Parts and Drawings25A1044 (RI)Table 5Printed Circuit Board Replacement PartsReferenceDesignation Description Shure PartNumberC314 Capacitor, trim, 5 – 40 pF 152F03C510 Capacitor, trim, 1 – 3 pF 152A04D201 Diode, signal / switching, SMD, SOT-23, 1.1 V 184A08D203 LED, red 184A18D204 LED, yellow 184B18D205 LED, green 184C18D301–304 Diode, dual switching, SOT-23, 1 V 184A07D501 Diode, rf tuning 184A36J200 Connector, receptacle, 11-pin header, female 170A08J205 Socket, strip 170C15J300 Connector, 11-pin header, male 170A07L1 Bead, ferrite 162A12L200,203,207,300,32,303,306 Inductor, 180 nH 162R10L304 Inductor, 8.2 nH 162W10L305 Inductor, 3.3 nH 162T10L307 Inductor, 22 nH 162D10L308 Inductor, 6.8 nH 162V10L501,503 Inductor, 100 nH 162A25L502 Inductor, 10 nH 162N25Q3,201,211,212,213 Transistor, SMD, SOT–23, FET, TMOS 183A30Q202 Transistor, chopper, PNP, SOT-23 183A07Q203,303,305 Transistor, SMD, power MOSFET 183A46Q204,208,209,210,220 Transistor, SOT-23, NPN 183A02Q301 Transistor 183A01Q302,501,502 Transistor 183A48R207 Potentiometer, Gain 46H8014R320 Potentiometer, Trim, 1 k 146B02S200 Switch, slide, DPDT 55A178S301 Switch, Dip, PCB, 16 pos 155A11S302 Switch, DIP, PCB, 10 pos 155B11U5 Detector, SMD voltage 188C210U107,108, 109 Filter, low-pass 162A28U311 IC voltage regulator, 5V 188A115U200,201 IC, quad op amp 188A49U202 IC, compandor, low voltage 188A126U203,311 IC voltage regulator, 5 V 188A115U205 IC, comparator, quad, ultra-low power 188A123U302 IC, EEPROM 188A131U303 Microprocessor, programmed 188D238EU304 PLL frequency synthesizer 188A265U306 Amplifier, operational, dual, SMD 188A118U501 Dielectric resonator 140A14Y200 Crystal, 32.768 kHz 40A8010Y301,302 Crystal, 4.0 MHz 40A8012
Shure UC2 Hand-Held UHF TransmitterReplacement Parts and Drawings3125A1044 (RI)Table 6Group Designators(in order by frequency)FrequencyRange(MHz)CountryDesignation CountryCode R19kΩR20kΩR21kΩR22kΩR26kΩR27kΩ774–782 Netherlands MC – 1.0 – – – –782–806 U. S. & Canada UA 1.0 –––––797–806 Japan JA – – 1.0 – – –800–830 Europe MB – 1.0 – – – –806–810 Japan JB – – – 1.0 – –838–862 England KK – – – – 1.0 –CountryCode R28ΩR29ΩR30kΩR31kΩR32kΩR33kΩR34kΩR35kΩR36ΩR37ΩMC – – – 1.0 – – – – – –UA – – 1.0 – – – – – – –JA – – – – 1.0 – – – – –MB – – – 1.0 – – – – – –JB – – – – – 1.0 – – – –KK – – – – – – 1.0 – – –
Shure UC2 Hand-Held UHF Transmitter32Replacement Parts and Drawings25A1044 (RI)Table 7Frequency Dependent Parts(in order by frequency)FrequencyRange (MHz) CountryDesignation CountryCode C4uF C24uF C35pF C210uF C211uF C254uF C330pF C345pF774–782 Netherlands MC .047 0.1 220 2.2 – – – 27782–806 U. S. & Canada UA – – – – .047 – – 27797–806 Japan JA .047 0.1 220 2.2 – – 10 4.7800–830 Europe MB .047 0.1 220 2.2 – – – 27806–810 Japan JB – – – – .047 – 10 4.7838–862 England KK .047 0.1 220 2.2 – – – 27CountryCode C505pF C506pF C507pF C509pF J2 L2 Q1 Q2 R1kΩR2kΩMC 4.7 4.7 4.7 1.0 – – 183A01 183A02 249 10.0UA 4.7 4.7 4.7 1.0 – 162A12 – – – –JA 4.7 4.7 4.7 1.0 95A8278 – 183A01 183A02 249 10.0MB 4.7 4.7 4.7 1.0 – – 183A01 183A02 249 10.0JB 4.7 4.7 4.7 1.0 95A8278 162A12 – – – –KK 3.9 2.2 3.9 – – – 183A01 183A02 249 10.0CountryCode R3kΩR6kΩR7kΩR8kΩR9kΩR10MΩR11kΩR12kΩR13MΩR16kΩR40kΩMC 1.5 10.0 4.02 10.0 100 1.0 10.0 22.1 1.0 – –UA 0 – – – – – – – – 0 –JA 1.5 4.02 4.02 4.02 100 1.0 10.0 22.1 1.0 – 146B02MB 1.5 10.0 4.02 10.0 100 1.0 10.0 22.1 1.0 – –JB 0 10.0 – – – – – – – 0 146B02KK 1.5 10.0 4.02 10.0 100 1.0 10.0 22.1 1.0 – –CountryCode R42kΩR233kΩR264kΩR265kΩR287kΩR289kΩR333kΩS301 S302 U2MC – 15 24.9 200 0 – 100 155A11 155B11 188A136UA – 15 24.9 200 10.0 4.02 100 155A11 155B11 –JA 100 20 – 24.9 0 – 249 155B11 155A11 188A136MB – 15 24.9 200 0 – 100 155A11 155B11 188A136JB 100 20 – 24.9 10.0 4.02 249 155A11 155B11 –KK – 15 24.9 200 0 – 100 155A11 155B11 188A136
Shure UC2 Hand-Held UHF TransmitterReplacement Parts and Drawings3325A1044 (RI)UC2 Hand-Held UHF TransmitterPrinted Circuit Board, Side 1
Shure UC2 Hand-Held UHF Transmitter34Replacement Parts and Drawings25A1044 (RI)UC2 Hand-Held UHF TransmitterPrinted Circuit Board, Side 2

Navigation menu