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

OK

CHECK SCREEN VOLTAGE ABOUT 400V TO 600V

LESS THAN 300V

OK

BRIGHTNESS SET TO MAX. THEN CHECK CRT G1 VOLTAGE

NG

CHECK FAILSAFE CKT Q402,Q403

RELATIVE CKT.

CHECK CRT’S HEATER RELATIVE CIRCUIT Q907,Q908

CHECK FBT. D706,R723,C713

CHECK BRIGHTNESS CIRCUIT Q703,Q704,Q705 RELATIVE CKT.

OK

CHECK VOLTAGE OF THE CRT

CATHODE ABOUT 60V TO 70V

 

 

 

 

NG

 

 

REFER ITEM 8-2

 

 

“ABNORMAL DISPLAY”