Trouble Shooting Chart; No Raster, Crt Relative Circuit Problems - HP V7650 Series Service Manual

6.TROUBLE SHOOTING CHART

6-1 NO RASTER, CRT RELATIVE CIRCUIT PROBLEMS

CHECK MAIN PCB POWER
CHECK MAIN PCB POWER SUPPLY
SUPPLY 47.0V,13V
53V, 14V, 78V
NG
OK
CHECK THE HIGE VOLTAGE OF
CHECK THE HIGE VOLTAGE
CRT ABOUT 23~24KV
OF CRT ABOUT 24.5 ~ 25.5KV
NG
OK
CHECK THE VOLTAGE OF CRT
HEATER ABOUT 6.3V
NG
OK
CHECK SCREEN VOLTAGE ABOUT
400V TO 600V
LESS THAN 300V
OK
BRIGHTNESS SET TO MAX. THEN
CHECK CRT G1 VOLTAGE
NG
OK
CHECK VOLTAGE OF THE CRT
CATHODE ABOUT 55V TO 65V
NG
CHECK POWER SAVING CIRCUIT,
H-SYNC, V-SYNC SIGNAL
Q909, Q910
REFER ITEM S.M.P.S.
CHECK FAILSAFE CKT IC401
PIN 25 RELATIVE CKT.
CHECK CRT'S HEATER RELATIVE
CIRCUIT Q907, Q908
CHECK FBT
CHECK BRIGHTNESS CIRCUIT
CHECK BRIGHTNESS CIRCUIT
Q705 RELATIVE CKT.
Q703, Q704, Q705 RELATIVE CKT.
REFER ITEM 6-2
"ABNORMAL DISPLAY"
14
OK