Sharp VC-G200SM, Service Manual

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39
VC-G20SM/G200SM
VC-G201SM/G401SM
7. ELECTRICAL
TROUBLESHOOTING
FLOW CHART NO.1 POWER TROUBLESHOOTING(1)
No power
Unplug the
AC power cord.
Replug it a few minutes later
.
See FLOW CHAR
T
NO.2 POWER
TROUBLESHOOTING (2).
YES
YES
YES YES
NO NO
NO
NO
Is the fuse good?
Replace fuse.
Is
A
T
5V voltage line normal?
Check primary circuit.
Are
A
T
39V
, A
T
25V and
A
T
12V lines
normal?
Check each rectifier circuits and short-circuit of secondary circuit.
Is "H" level applied at pin(1) of system CTL
circuit IC701?
FLOW CHART NO.3 POWER TROUBLESHOOTING(3)
In case of abnormal noise(sound)
Check
D931, D9332, D933
and D934.
The
D931, D9332, D933
and
D934 as a result of check if poor the replace.
NO
FLOW CHART NO.2 POWER TROUBLESHOOTING(2)
In case of Fuse(F901) blown out.
Replace F901, Q901 and R904. Check D901, D902, D903 and D904 as a result of check, if poor
, replace
at the same time.
Check short-circuit or leak of D931, D9332, D933, D934 and secondary circuit.
FLOW CHART NO.5 TIMER TROUBLESHOOTING (1)
The LCD display fails to light up.
Is the supply voltage of 5V fed to pin(37) of IC8001?
Check
A
T
5V line.
Is the supply voltage of 3.4V
, 1.7V
feed to pin(38) and pin(39) of IC8001?
Check pin(38), (39) of IC8001 and peripheral circuits.
Is it possible to confirm signals LCD RESET
, LCD CS, LCD CLOCK
and LCD DA
T
A
on the pins(36),
(42), (43) and (44) of IC8001?
Are the segment signals supplied to the LCD display (LC8001) fromthe driver IC (IC8001)?
Check peripheral circuit of pin(41) of IC8001.
Check that the LCD display is free from damages such as crack.
Replace IC8001.
YES YES
YES
YES
NO
NO
NO
NO
NO
YES
YES YES
NO
NO NO
FLOW CHART NO.4 POWER TROUBLESHOOTING(4)
In case of output voltage at low level.
Check peripheral circuits IC901, IC903, C9336, R930, R932 and R933.
The IC901, IC903, C9336, R930, R932 and R933 as a result of check, if poor the replace.
Check IC901 and peripheral circuits.
Replace Q902.
Check short-circuit or leak of T901.
Replace T901.
Check primary circuit and peripheral circuit of Q901 and Q902.
Check the signal line between IC701 and IC8001.
YES
IC8001 present? Is the OSC signal at pin(41) of