Troubleshooting Flow Chart For Dc Supply (1 Of 2) - Motorola CM200 Service Manual

Troubleshooting Flow Chart for DC Supply (1 of 2)

5.0 Troubleshooting Flow Chart for DC Supply (1 of 2)
Since the failure of a critical voltage supply might cause the radio to automatically power down,
supply voltages should first be probed with a multimeter. If all the board voltages are absent, then
the voltage test point should be retested using a rising-edge-triggered oscilloscope. If the voltage is
still absent, then another voltage should be tested using the oscilloscope. If that voltage is present,
then the original voltage supply in question is defective and requires investigation of associated
circuitry.
Go to 3V
Replace U503
Go to D3_3V
Replace U508
5V
Check VDC on
C5006
No
Yes
V=5V
?
No
Yes
9v<V<9.8v
?
3V
Check VDC on
C5008
No
Yes
V=3.3V
?
No
Yes
9v<V<9.8v
?
Check Voltage on
C5042
Go to Start
Check Voltage on
C5043
Go to Start
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