ViewSonic P774B-2NT Series, Service Manual

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13
6.TROUBLE SHOOTING CHART
6-1 NO RASTER, CRT RELATIVE CIRCUIT PROBLEMS
REFER ITEM S.M.P.S.
BRIGHTNESS SET TO MAX.
CHECK CRT G1 VOLTAGE
NG
NG
NG
NG
NG
OK
OK
OK
OK
OK
CHECK THE HIGE VOLTAGE OF CRT
ABOUT 24.5 ~ 25.5KV
CHECK THE VOLTAGE OF CRT
HEATER ABOUT 6.3V
CHECK VOLTAGE OF THE CRT
CHECK BRIGHTNESS CIRCUIT
OK
CHECK POWER SAVING CIRCUIT,
H-SYNC, V-SYNC SIGNAL
Q909, Q910
"ABNORMAL DISPLAY"
CHECK SCREEN VOLTAGE ABOUT
LESS THAN 300V
CHECK FBT
CHECK MAIN PCB POWER SUPPLY
55.5V, 12.3V, 6.3V
CHECK FAILSAFE CKT
CHECK CRT'S HEATER RELATIVE
CIRCUIT Q907, Q908
Q703, Q704, Q705 RELATIVE CKT.
PIN 25 RELATIVE CKT.
400V TO 600V
REFER ITEM 6-2
CATHODE ABOUT 55V TO 65V