Motorola Mtx Series Detailed Rev 6881088c46 E Manual
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Chapter 9 VHF Troubleshooting Charts 9.1 Troubleshooting Flow Chart for Controller MCU Check Power Up Alert Tone OK? Speaker OK? U409 EXTAL= 7.3728 MHz? U3701 Pin 19 16.8 MHz 5V at U3711? 3.3V at U3201? U409 Reset Pin 94 High? MCU is OK Not able to pro- gram RF Board ICsBefore replacing MCU, check SPI clock, SPI data, and RF IC select Replace Speaker Read Radio OK? Check Setup Reprogram the correct data. See FGU Troubleshooting 7.5V at Pin 3/5 U3711? 7.5V at Pin 1 U3201Check Q400 Replace U3711/U3201 Check any short to SWB+, Vdda or Vddd Press PTT. Red LED does not light up PTT U409 Pin 53 low? Press PTT Q502-2 High? Check PB504 Check Q502-2 voltage LED Q502,R501 OK? Replace Faulty Component Check Accessories J403 OPT_SEL_1 & OPT_SEL_2 Pin 8 & 9 low? Radio could not PTT externally U409 Pin 52, 6 low? See FGU Trouble- shooting chart LED should light up Check MCU PTT NO YES YES No No NO YESYES NOYESYES NO NO YES YES NO NO YES NO YES NO YESYESNO NO YES EXT SPKR EXT PTT INT AUDIO J403 Pin 9 low? Pin 8 high? ASFIC U404 Pin 14 & 15 high? Check Accessories Check U404 Check U420 Audio PA NO NO YES YES J403 Audio at Pin 2 & Pin 3 Check Spk. Flex Connection Audio at Audio PA (U420) input (U447) Audio from Pin 41 ASFIC, U404? Check ASFIC U404 Check Audio PA (U420) Check U3220 IF ICAudio at Pin 2 U404? NO NO NO YESYES NO YES
December 26, 2003FMR-2045A-2 92VHF Troubleshooting Charts: Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) 9.2Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) Bad SINAD Bad 20dB Quieting No Recovered AudioSTART Audio at pin 8 of U3220?Check Controller (in the case of no audio) or else go to “B”Ye s No Spray or inject 44.85MHz into XTAL Filter Y3200 Audio heard?BYe s No Check 2nd LO (44.395MHz) at C3274 LO Present?BYe s Voltages OK? Biasing ok? Check circuitry around U3220. Replace U3220 if defective No No A Ye sCheck Q3200 bias for faults. Replace Q3200. Go to “B” Ye s No Check voltages on U3220 Check circuitry around Y3202. Replace Y3202 if defective
FMR-2045A-2December 26, 2003 VHF Troubleshooting Charts: Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) 93 Troubleshooting Flow Chart for Receiver (Sheet 2 of 2) IF Signal at L3200? No RF Signal at T3301? RF Signal at R3313? No RF Signal at C3306? No RF Signal at C3302? No or Check harmonic filter L3531 and L3532, C3532 and antenna switches D3521, D3551, L3551, R3551, C3551, C3552, and L3552 Check filter between C3302 & C3306; pro- gram filter to schematic test freq and check varactor voltages. Inject RF into J3501 Are varactor voltages OK? No Ye s Check RF amp (Q3302) Stag e Check filter between C3313 and T3301. Ye s Check T3301, T3302, CR3301, R3321, R3322, and R3323 Ye s 1st LO O/P OK? Locked?Ye s Check FGU Ye s Trace IF signal from L3200 to Q3200. Check for bad XTAL filter. No Ye sQ3200 collector OK? IF signal present? Before replacing U3220, check U3220 volt- ages; trace IF signal path. Ye s Check for 2.9 VDC Is R5 present? Check Q3721, U3701 (pin 48) volt- ages and U247 No No No Check U404 voltage and if U404 can be selected by MCU before replacing U404. Check varactor filter. NoYe s Ye s Ye s A A B weak RF
December 26, 2003FMR-2045A-2 94VHF Troubleshooting Charts: Troubleshooting Flow Chart for Transmitter 9.3 Troubleshooting Flow Chart for Transmitter START No Power Is There B+ Bias for Ant switchCheck Q3561 Is Current OK?Is Control Voltage high or low?Check PCIC 1. Check Pin Diodes 2. Check Harmonic Filter Inspect/Repair Tx. Output Network Is Power OK? Done Check Drive to Module Is Drive OK? Troubleshoot VCO Inspect PA Network/ Check power out of U3501 at Cap C3512 Is Power OK? Replace U3501 Is Power OK? Replace Q3501 Done Done No Ye s Ye sNo No Ye sLow High No Ye s Ye s No Ye s No
FMR-2045A-2December 26, 2003 VHF Troubleshooting Charts: Troubleshooting Flow Chart for Synthesizer 95 9.4 Troubleshooting Flow Chart for Synthesizer 5V at pin 6 of D3701 Is information from µP U409 correct? Is U3701 Pin 18 AT 4.54 VDC? Is U3701 Pin 47 AT = 13 VDC Is U3701 Pin 19 4.3 VDC in TX? Sta rt Visual check of the Board OK?Correct Problem Check 5V Regulator +5V at U3701 Pin’s 13 & 30? Is 16.8MHz Signal at U3701 Pin 19? Check Y3761, C3761, C3762, C3763, D3761 & R3761 Are signals at Pin’s 14 & 15 of U3701? Check L3701, R3701Check Q260, Q261 & R260 U3701 pin 2 at >3V in Tx and -30 dBm? Are C3721, C3722,C3723, R3721, R3722, R3723 OK? Replace U3701 If R3727, C3726 & C3727 are OK, then see VCO troubleshooting chart Are Waveforms at Pins 14 & 15 triangular? Do Pins 7,8 & 9 of U3701 toggle when channel is changed? Check programming lines between U409 and U3701 Pins 7,8 & 9 Replace U3701 Check uP U409 Troubleshooting Chart NO YES NO YES NO YES NO YESNO NO NO YES YESNOYES YESNO YES YES YES NONO NO NO YES NO YES YESCheck D3701, D3702, U3701, C3701 - C3707 3.3V at U3701 pins 5, 20, 34 & 36Check U3201, L3731 Is 16.8MHz signal at U3701 pin 23? Replace U3701 YES NO NO YES NO YES Replace U3701
December 26, 2003FMR-2045A-2 96VHF Troubleshooting Charts: Troubleshooting Flow Chart for VCO 9.5Troubleshooting Flow Chart for VCO START No LO? Tx Carrier? VCO OK Check R3829 TRB = 3.2V?Pin 10 >1V? L3831, L3832, L3833 O/C? Change L3831, L3832 Change U3801 AUX 3 High? Check U3701 Pin 2 for 3.2V Pin 19 =0V AUX 3 Low? Change U3801 V ctrl 0V or 13V?L3821, L3822, L3823 Open Circuit? Change U3801 Change L3821, L3822, L3823, andL243 Change U3701 Check for faulty parts or dry joints of L3812 C3806, R3806, R3802 and L3801A A No No Ye s Ye s Ye s No NoYe sYe s Ye s No Ye sNoNoYe sYe s No No Check R3811, L3811 for faulty parts and dry joints NoYe s