Fujitsu MCM1514V, C551, D556Q, 154V manual Abnormal Power Supply

6.TROUBLE SHOOTING CHART

6-1 NO RASTER, CRT RELATIVE CIRCUIT PROBLEMS

1.ABNORMAL POWER SUPPLY

90V,12V

CHECK MAIN PC BOARD

NG

OK

CHECK THE HIGE VOLTAGE OF CRT ABOUT 23.5 ~ 25.5KV

CHECK POWER SAVING CIRCUIT Q909,Q910

NG

OK

CHECK THE VOLTAGE OF CRT HEATER ABOUT 6.3V

NG

CHECK FAILSAFE CKT Q402,Q403

RELATIVE CKT.

CHECK CRT’S HEATER RELATIVE CIRCUIT Q907,Q908

OK

CHECK SCREEN VOLTAGE ABOUT 400V TO 600V RELATIVE CKT.

LESS THAN 300V

OK

BRIGHTNESS SET TO MAX. THEN CHECK CRT G1 VOLTAGE

NG

OK

CHECK VOLTAGE OF THE CRT CATHODE ABOUT 60V TO 70V

NG

CHECK FBT. D706,R723,C713

CHECK BRIGHTNESS CIRCUIT Q703,Q704,Q705 RELATIVE CKT.

REFER ITEM 8-2

“ABNORMAL DISPLAY”