ViewSonic P90F Service Manual page 33

SECTION 2
Blank Screen LED Amber
Check by entering Preset
mode to obtain "No
NO
Check pin 23,21of IA01
pin17= High, pin18= Low
YES
Go to SECTION 1 SMPS
troubleshooting chart
ViewSonic Corporation
YES
No
NO
Check signals from PC
NO
Check if XA01
waveform exist ?
YES
Replace
MCU (IA01)
29
Check B+ (5V)
to IA01 exist ?
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P90f-1