ViewSonic P774B-2NT Series, Service Manual

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15
6-2 ABNORMAL DISPLAY
1.NO SIGNAL ON SCREEN
CHECK FBT RELATIVE CIRCUIT
LESS THAN 400V
OK
NG
NG
OK
OK
NG
OK
NG
CHECK THE OUTPUT VOLTAGE OF
IC801 PIN 19, 20, 21 ABOUT 3Vpp
CHECK THE B+ VOLTAGE OF
CHECK THE VOLTAGE OF CRT
CATHODE ABOUT 40Vpp
CHECK THE VOLTAGE OF FBT
SCREEN ABOUT 400V TO 700V
CHECK THE RELATIVE CIRCUIT
CHECK THE 12V PIN OF P802
CONNECTOR
OF SMPS ON MAIN PCB
RELATIVE CIRCUIT
EXCEED 700V
CHECK FBT & CRT RELATIVE
CIRCUIT OR REFER ITEM 6-1
CHECK VIDEO IC801 VCC ABOUT 5V
CHECK THE IC802
OF IC801 PIN 10/PIN 18 Vcc CIRCUIT
VIDEO PCB ABOUT 80V
CHECK THE 80V RELATIVE CIRCUIT