Troubleshooting Flow Chart for DC Supply (1 of 2) 3-9
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.
Check VDC on
C5008
V=3.3V
?
Check Voltage on
C5043
No
Go to D3_3V
Yes
9v<V<9.8v
?
Go to Start
No
Replace U508
Yes
3V
Check VDC on
C5006
V=5V
?
Check Voltage on
C5042
No
Go to 3V
Yes
9v<V<9.8v
?
Go to Start
No
Replace U503
Yes
5V
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