3-4
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Only for training and service purposes
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ELECTRICAL TROUBLESHOOTING GUIDE
Is 5.6V present at
collector of Q126?
No 3.3VA
YES
YES
YES
YES
No 5V
No 3.3VA.
Replace Q126.
Check FR101
Replace Q121.
YES
Is there a DC voltage at
cathode of D105 or D107?
YES
NO
NO
NO
NO
Replace IC101.
2. POWER CHECK FLOW
A.
B.
Check D105/D106/D107/
D108 and replace.
Is 3.3VA
section working?
Is 3.3VA
section working?
Is 3.3V
present at emitter
of Q121?