Motorola Radius Cm200 Cm300 Pm400 Detailed 6881098c00 A Manual
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Receive Signalling Circuits2-21 9.4 Handset Audio Certain handheld accessories have a speaker within them which require a different voltage level than that provided by U502. For these devices HANDSET AUDIO is available at control head connector J2 pin18. The received audio from the output of the ASFIC CMP’s digital volume attenuator is routed to U505 pin 2 where it is amplified. This signal is routed from the output of the op-amp U505 to J2-pin 18. From the control head, the signal is sent directly...
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2-22THEORY OF OPERATION The low speed limited data output (PL, DPL, and trunking LS) appears at U504-pin18, where it connects to the µP U403-pin 80. The low speed data is read by the µP at twice the frequency of the sampling waveform; a latch configuration in the ASFIC CMP stores one bit every clock cycle. The external capacitors C5028, and C5026 set the low frequency pole for a zero crossings detector in the limiters for PL and HS data. The hysteresis of these limiters is programmed based on the...
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Chapter 3 TROUBLESHOOTING CHARTS This section contains detailed troubleshooting flowcharts. These charts should be used as a guide in determining the problem areas. They are not a substitute for knowledge of circuit operation and astute troubleshooting techniques. It is advisable to refer to the related detailed circuit descriptions in the theory of operation sections prior to troubleshooting a radio. Most troubleshooting charts end up by pointing to an IC to replace. It is not always noted, but it is...
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3-2TROUBLESHOOTING CHARTS 1.0 Troubleshooting Flow Chart for Receiver RF (Sheet 1 of 2) Problem in 12 KHz and 25 KHz channel spacing 9V on R310 (LNA) OK ?Check RX_ENNoGo to DC Section Ye s RX_EN ON ?NoCheck Q306, Q300 and U403Ye s START LOC_DIST ON ?Check Q304, D305 and U403 LO POWER OK ? Go to SYN Section Ye s Ye s No No Go to A 3 V to U301 Okay ?No Check LOC_DIST Go to DC Section Ye s Check D301-304 Replace IF Filters( FL304, FL301 If problem in 25 KHz spacing Check TPI Check 5V on R337 (UHF),...
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Troubleshooting Flow Chart for Receiver RF (Sheet 1 of 2) 3-3 1.1Troubleshooting Flow Chart for Receiver (Sheet 2 of 2) 3V (IFIC -Vcc) OK ? Installation OK ? Ye s Ye s No No A From Check visually FE and BE components installation ? Inject - 40dBm (CW) to RF connector Check Power on C335 (UHF) C332 (VHF) RF Power > -28 dBM ?Ye s NoCheck Power on C337 (UHF), C336 (VHF) Go to DC Section Check the component FE Problem Replace Q303, Q301 Check passive componentsRF Power > -28 dBM ?Ye s NoReplace Q305,...
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3-4TROUBLESHOOTING CHARTS 2.0 Troubleshooting Flow Chart for 40 W Transmitter (Sheet 1 of 3) START Ye s No Check components between Q100 and RF output, Antenna Switch D104, D103, VR102 and Q106 No or too low power when keyed Current increase when keyed? Check power settings, tuning & components between U103 Pin 3 and ASFIC Pin 6 before replacing ASFIC Control Voltage at TP150 >4Vdc?Check PA Stages >4A Voltage U103 pin 5 = 4.7V? U103 Pin 3 1.8Vdc Check 9.3V Regulator U501 Ye s Ye sNo No Ye...
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Troubleshooting Flow Chart for 40 W Transmitter (Sheet 1 of 3) 3-5 2.1Troubleshooting Flow Chart for 40 W Transmitter (Sheet 2 of 3) No Ye s Ye sNo Check bias tuning before replacing U504 Check PA Stages No or too low power when keyed DC Voltage at Q101 & Q102 base=0? DC Voltage at U103 Pin 8 Check U510 Check resistive network at Pin 9 and 10 of U103 before replacing U101 Measure DC Voltage at Pin 2 & 3 of U5401 Pin 2 Voltage 0.62 x Voltage at Pin 1 Replace U5410 Pin 3 Voltage 0.51 x Voltage...
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3-6TROUBLESHOOTING CHARTS 2.2Troubleshooting Flow Chart for 40 W Transmitter (Sheet 3 of 3) No Ye s Ye sNo Check Final PA Stage PA_Bias Voltage at R134 RF Voltage after C1044 >100mV? Voltage across R122 >2V? RF Voltage Q105 gate >1V? RF Voltage Q100 gate >7V? Check components between Q100 & antenna connector Replace Q100 Check FGU (U5301) Check components between C1044 & C1117 Check components between C117 & Q105 Check components between Q105 & Q100 No No Ye s Ye s 1-4VSupply Voltage...
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Troubleshooting Flow Chart for Synthesizer3-7 3.0 Troubleshooting Flow Chart for Synthesizer 5V at pin 6 of D200 Is information from uP U403 correct ? Is U200 Pin 47 at = 14.6VDC ? Is U201 Pin 19 4.5 VDC in TX? (at VCO section) ? Sta rt Visual check of the Board OK?Correct Problem Check 5V Regulator U503 +5V at U200 Pin’s 13 & 30 ? Is 16.8MHz Signal at U200 Pin 19 ? Check Y201 and associated Parts Are signals at Pin’s 14 &15 of U200 ? Check R228Check R201 Is U200 Pin 2 >4.5 VDC in Tx &
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3-8TROUBLESHOOTING CHARTS 4.0 Troubleshooting Flow Chart for VCO Are Q200 Base at 2.9V Collector at 6.6V Emitter at 2.2V Are U201 Pins 15 at 1.0V 10 at 3.9V 16 at 1.8V Low or no RF Signal at TP1 Visual check of board OK? 370mV DC at U201 Pin 19 NO YES at base of Q200 NO NO NO YES YESYESLow or no RF Signal at input to PA 4.5V DC at U201 Pin 19 Is RF available at C2060 YES YESYES YES NO NO NO NO NO Audio =180mVRMSat “-” Side of 4.5VDC at D205 If R211 and R12 are OK, then replace D205 Replace R211...