Sharp XG-NV2SB Service Manual page 46

XG-NV2SB
TROUBLE SHOOTING TABLE FOR PC I/F UNIT-5
Checking the S-
VGA's blue video
circuit and its
peripheral circuits
Is there signal at pin (3) of IC8004?
Yes
Is there signal at the base of Q31?
Yes
Is there signal at pin (6) of IC8009?
Yes
Are there signals at BI1A0 thru -7 and
BI1B0 thru -7 of IC8025?
Yes
Are there signals at R1 thru -10 and
G1 thru -10 of IC8031?
Yes
Are there signals at the bases of Q23
and Q25?
Yes
Are there signals at pins (1) and (3) of
TC2 connector?
Yes
TC2 connector or output PWB faulty.
No
LCP circuitry faulty.
No
IC8004 or its peripheral circuit faulty.
No
Q31 or its peripheral circuit faulty.
No
IC8009 or its peripheral circuit faulty.
IC8020 or its peripheral circuit faulty.
No
IC8025 or its peripheral circuit faulty.
No
IC8031 or its peripheral circuit faulty.
No
Q13, Q22 thru Q25 or their peripheral
parts faulty.
46
Checking the VGA's
blue video circuit
and its peripheral
circuits
No
Is there signal at pin (3) of IC8004?
Yes
No
Is there signal at the base of Q31?
Yes
No
Is there signal at pin (6) of IC8009?
Yes
No
Are there signals at VAB0 thru -7 of
IC8020?
Yes
No
Are there signals at BI2A0 thru -7 and
BI2B0 thru -7 of IC8025?
Yes
Check the video
system's blue video
circuit and its
peripheral circuits.
No
Are there signals at VBB0 thru -7 of
IC8020?
Yes
D
D