BUFFALO FTD-G931AS/BK
20
Check F902
Check D201/Q209/Q210
Check D202/Q211/Q212
Check ON/OFF signal
Check Interface board
Check U201 pin9=12V voltage
Change Q201 or Q202
Check the pin10/Pin7 of U201 have saw tooth
Short Q203/Q204 if the picture normal
Replace U201
Connect PIN15 of U201 to the ground and check
Q209/Q210/Q211/Q212 collector waveforms
OK
OK
OK
OK
NG
NG
NG
NG
NG
Check feedback circuit
1) Replace Q209/Q210/PT201
2) Replace Q211/Q212/PT202
Check connecter & lamp
OK
NG
NG