IBM 9493-AG1, Service Manual

Page: 17 / 41

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CHECK U19, U20,
U23, +3.3V
U5
POWER PIN
3.3V?
NO
1. CHECK PC
2. CHECK SIGNAL CABLE
& D-SUB CONNECTOR
LINE
CHECK
R,G,B INPUT?
U5 PIN 7, 15, 22
NO
CHECK IIC LINE
CHECK
IIC PULSE ?
U5 PIN 29, 30
NO
CHECK H-SYNC LINE
(D-SUB
→
U11
→
U18
PIN40)
CHECK
CKREF(H-SYNC) INPUT?
U5 PIN40
NO
CHECK CKREF INPUT
CHECK
COAST INPUT?
U5 PIN41?
NO
YES
YES
YES
YES
YES
YES
NO RASTER
(OSD IS DISPLAYED)
4. NO RASTER (OSD IS DISPLAYED) – AD9884
CHECK SIGNAL LINE
FROM U14 PIN17
TO U5 PIN28
CHECK
CLAMP INPUT(H-SYNC)?
U5 PIN28
NO
CHECK SIGNAL LINE
FROM U5 PIN115
TO U1 PIN254
(1024x768/85Hz : 95MHz)
CHECK
CLOCK INPUT
(25MHz-95MHz SINEWAVE)
?
U5 PIN115
NO
YES