ViewSonic P90F Service Manual page 34

SECTION 3
LED Green
No Raster
Is DC Voltage at Pin2 of
FBT Proper(80 V Approx.)
NO
Check SMPS DC O/P
(SECTION 1)
ViewSonic Corporation
YES
Is the voltage at collector of
Q433 proper ?
Is the voltage 6.3V at
heater?
Check P902
OK ?
Check P904 connection
OK ?
Check Q121 output
300 Vp-p approx.
Check I101 pin 2 > 2.5V
Check OVP CKT setting
build by Q114,115,116
30
NO
YES
NO
YES
connection
YES
YES
NO
NO
Confidential – Do Not Copy
Go to SECTION 4 No
raster ,but High Voltage
exist
Check S.M.P.S
(SECTION 1)
P90f-1