All output voltages on the power board is 0V or deviated.
All output voltages on
the power board is 0V or
deviated
Yes
Check whether
F501 is blown
No
Check whether there is
300V on C501 or C502.
Yes
Check whether 100KHz
oscillating
signal
Pin6 of U1
Yes
Check if +5V and +12V
are short.
Yes
Check whether the components in the
short-circuit voltage are defected or eroded.
5-3
Yes
Replace F501
No
No
on
No
Replace C501&C502 if D501, D502,
D503, D504 are normal.
Check/ replace U1.
U1(PIN 3 - RC waveform)
Check whether U1 are eroded.
Trouble shooting chart
U1(PIN 8 - Drain waveform)