![background image](http://html1.mh-extra.com/html/viewsonic/g90fb-4/g90fb-4_service-manual_1020357022.webp)
6-5. No signal on screen
NG
OK
NG
OK
NG
OK
NG
OK
NG
6-6. Abnormal horizontal width of video
NG
OK
NG
OK
NG
CHECK THE VOLTAGE AT
PIN10/14/17/22 OF IC801 ABOUT 5V
CHECK 5V SUPPLY CIRCUIT
CHECK THE VOLTAGE OF IC801
PIN23/24/25 ABOUT 4VP-P
CHECK THE RELATIVE CIRCUIT
OF IC801 PIN23/25/24 OR THE
IC801 FAIL
CHECK THE VOLTAGE OF IC802 PIN12
ABOUT 83V AND IC802 PIN2 ABOUT 12V
CHECK THE 83V&12V SUPPLY
CIRCUIT OR MAIN BOARD
CHECK THE VOLTAGE OF CRT CATHODE
ABOUT 50VP-P
CHECK THE RELATIVE CIRCUIT
OF IC802 OUT PUT
CHECK THE VOLTAGE GO G2 ABOUT
550V~650V
CHECK FBT RELATIVE CIRCUIT
READJUST H-SIZE FUNCTION
CHECK RELATION CIRCUIT OF Q406
CHECK B+ VOLTAGE ABOUT 125.5V AT
H-FREQUENCY=68KHZ
CHECK B+ SUPPLY CIRCUIT
CHECK THE HIGH VOLTAGE ABOUT
25.5~26.5V
REFERENCE TO ITEM7
ViewSonic Corporation
Confidential - Do Not Copy
G90fB-4
19