Abnormal Display - ViewSonic P774B-2NT Series Service Manual

1.NO SIGNAL ON SCREEN
CHECK VIDEO IC801 VCC ABOUT 5V
OK
CHECK THE OUTPUT VOLTAGE OF
IC801 PIN 19, 20, 21 ABOUT 3Vpp
OK
CHECK THE B+ VOLTAGE OF
VIDEO PCB ABOUT 80V
OK
CHECK THE VOLTAGE OF CRT
CATHODE ABOUT 40Vpp
OK
CHECK THE VOLTAGE OF FBT
SCREEN ABOUT 400V TO 700V
LESS THAN 400V
EXCEED 700V

6-2 ABNORMAL DISPLAY

NG
NG
NG
NG
15
CHECK THE 12V PIN OF P802
CONNECTOR
CHECK THE RELATIVE CIRCUIT
OF IC801 PIN 10/PIN 18 Vcc CIRCUIT
CHECK THE 80V RELATIVE CIRCUIT
OF SMPS ON MAIN PCB
CHECK THE IC802
RELATIVE CIRCUIT
CHECK FBT RELATIVE CIRCUIT
CHECK FBT & CRT RELATIVE
CIRCUIT OR REFER ITEM 6-1