Trouble shooting chart |
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
F1 is blown
No
Check whether there is
300V on C1 or C2.
Yes 
Check whether 100KHz oscillating signal on Pin6 of U1
Yes
Yes
No
No
Replace F1
Replace C1&C2 if D1, D2, D3, D4 are normal.
Check/ replace U1.
U1(PIN 3 - RC waveform) | U1(PIN 8 - Drain waveform) |
Check if +5V, +12V are | No |
short. |
|
Yes |
|
|
|
Check whether the components in the |
|
| |
|
|
Check whether U1 are eroded.
