ViewSonic E90fB-4 Service Manual page 21

6-1-2. ABNORMAL VIDEO LEVEL ON SCREEN
CHECK THE VOLTAGE OF IC801
PIN 10, 18 ABOUT 5V
CHECK THE SIGNAL INPUT OF R.G.B.
ABOUT 0.7Vpp
CHECK IC801 PIN 23 CLAMP PULSE
CHECK THE VIDEO OUTPUT OF IC801
PIN 19, 20, 21 ABOUT 4Vpp,
CONTRAST SET MAX.
R.G.B. APPROACH STANDARD
6-1-3. ABNORMAL DDC (PLUG & PLAY)
CHECK IC101 PIN 16 VOLTAGE ABOUT 5V
CHECK SIGNAL CABLE
OR H802 PIN 2, 4 DATA OUTPUT
ViewSonic Corporation
NG
OK
OK
NG
OK
NG
OK
NG
OK
CHECK 5V RELATIVE CIRCUIT
CHECK SIGNAL CABLE OR
INTERFACE CARD.
CHECK THE IC801 PIN 23
RELATIVE CIRCUIT
CHECK IC801 PIN19/PIN20/PIN21
RELATIVE CIRCUIT
CHECK IC902 GOOD OR FAIL
18
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E90fB-4