Motorola Sse 5000 6881094c12 A Manual
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Page 121
6881094C12-ANovember 11, 2004 Troubleshooting Charts: VOCON TX Audio 9-17 VOCON TX Audio—Page 2 MAEPF-27397-B Replace U501 (GCAP II) Replace U509 (EEPOT) Go to TX RF flowchartReplace U401 Clock and Frame Sync present? Data present at TX test point? Use an oscilloscope to check the SSI audio signals from the GCAP (U703). The following test points are used for data collection: DCLK: 256 kHz Square Wave Clock TX: Audio Data Words SYNC: 8 kHz Frame Sync Pulse No Ye s Ye s End Problem Resolved? Ye s 1 2 1 No...
Page 122
November 11, 20046881094C12-A 9-18Troubleshooting Charts: VOCON RX Audio 9.12 VOCON RX Audio—Page 1 MAEPF-27394-B Probe R406 for Frame Sync Signal, Compare with RX SAP waveform, Trace 1 Frame Sync Present? Replace U401 and reflash Probe R403 for Data, Compare with RX SAP waveform, Trace 2 Signal Present? THD
Page 123
6881094C12-ANovember 11, 2004 Troubleshooting Charts: VOCON RX Audio 9-19 VOCON RX Audio—Page 2 MAEPF-27395-O Make sure that you look at all solder contacts. Check resistors and capacitors associated with this check. If all look fine, then replace U502. Make sure that you look at all solder contacts. Check resistors and capacitors associated with this check. If all look fine, then replace U503. Signal Present? Check Preamp Output Signal at C530 No No No No No Ye s Ye s Ye sYe s Ye s 1 Preamp Gain = 2.8...
Page 124
November 11, 20046881094C12-A 9-20Troubleshooting Charts: RX RF 9.13 RX RF—Page 1 Frequency OK? UHF: 73.35 MHz Inject a standard FM test signal into the antenna port. Use CPS to ensure that attenuator feature is disabled. Use a spectrum analyzer and high-impedance RF probe to measure the IF signal on side 2. No No Ye s Ye s Poor RX sensitivity or no RX audio Check RXLO Replace bad part Remove cable assembly, measure insertion loss Visual inspection OK? No Ye s Bad antenna connector. Replace chassis...
Page 125
6881094C12-ANovember 11, 2004 Troubleshooting Charts: RX RF9-21 RX RF—Page 2 Q501-c = 5.0 Vdc?No No No Ye sYe s Ye s Repair Defects Visual examination OK?Check Voltage Regulator U1 Q501-e = 3.7 Vdc?No Ye sReplace Q501 Replace Q502 Remove SH501 and inspect 2nd LO VCO Signal Present? Measure 2nd LO at TP501 on PCB side 2 No No Ye s Ye s LO Freq. OK? UHF: 71.1 MHz Measure RXCK, P1-5 RXFS, P1-6 RXDO, P1-12 Observe 0 to 3 Vdc digital signals Measure bit clock rate (Fbit) at RXCK Levels OK? 1 3 5 No Ye s...
Page 126
November 11, 20046881094C12-A 9-22Troubleshooting Charts: RX RF RX RF—Page 3 TP502 = 0 Vdc?No No Ye sYe s Repair defects Measure RF levels at first preselector filter and compute filter loss. UHF: TP13, U401-3 No Ye s Loss
Page 127
6881094C12-ANovember 11, 2004 Troubleshooting Charts: RX RF9-23 RX RF—Page 4 Ye s Fbit < 1.2 MHz?Measure tuning voltage (Vt) at R512 No No No Ye s Ye s Vt= 3 Vdc? Repair defects Replace Varactor D501Replace Abacus U500Repair defects Visual examination OK? 4 Visual examination OK? Remove SH501, inspect components No Ye s5 5No Ye s Remove SH501, inspect clock oscillator circuit at U500-19, 20Vt = 0 Vdc? 5 Clock synthesizer MAEPF-27473-O
Page 128
November 11, 20046881094C12-A 9-24Troubleshooting Charts: RX RF RX RF—Page 5 dac1 = dac2? Measure preselector filter tuning voltage dac1 and dac2. UHF: TP401, TP405 No Ye s Replace IF filter. UHF: FL490Repair defects 68 Visual inspection OK? Remove IF filter shield. Check IF filter and LC matching networks. UHF: SH403 No Ye s Check discrete preselector filters.Replace PCIC Dac voltages OK? Tune the radio across several channels. Measure dac2, proportional to frequency. No Ye s7 Replace PCIC...
Page 129
6881094C12-ANovember 11, 2004 Troubleshooting Charts: TX RF9-25 9.14 TX RF—Page 1 TX power OK? Place XCVR and VOCON into the analysis fixture. Key up. Measure RF power at remote port (fixture default). Ye s NoNo Ye s Ye sNo No or low TX power Check FGU Frequency OK? No Ye sCheck FGU Level about +4 dBm?Check remote port launch J102 & radio assembly Measure RF level at driver amp outlet, just after C107. Use a spectrum analyzer and high-impedance RF probe. Measure TXRF at FGU side of C106. RF level at...
Page 130
November 11, 20046881094C12-A 9-26Troubleshooting Charts: TX RF TX RF—Page 2 MAEPF-27420-B No Ye s Driver has low gain. Replace U102. RAWB+ about 7.2 Vdc? Measure RAWB+ voltage at U102-6 No No Ye s Ye s TXB+ about 7.2 Vdc?Check continuity to J1-1 thru E1. Measure Vgate at T P 111 , normally 4 to 5.5 Vdc Measure TXB+ at U102-14 All parts around U102 & U104 soldered?Vgate > 4 Vdc? 2 4 Check continuity to J1-1 thru Q1, F901 & E4. Loss