Sharp VC-MH705HM/LM Service Manual page 25

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FLOW CHART NO.13 TIMER TROUBLESHOOTING
The LCD display fails to light up.
Is the supply voltage of 5V fed to
NO
pin(37) of IC8001?
YES
Is the supply voltage of 3.4V, 1.7V
NO
feed to pin(38) and pin(39) of IC8001?
YES
Is it possible to confirm signals
LCD RESET, LCD CS, LCD CLOCK
and LCD DATA on the pins(36),
(42), (43) and (44) of IC8001?
YES
NO
Is the OSC signal at pin(41) of
IC8001 present?
YES
Are the segment signals
supplied to the LCD display
(LC8001) fromthe driver IC
(IC8001)?
YES
Check that the LCD display is
free from damages such as
crack.
FLOW CHART NO.14 DRUM MOTOR TROUBLESHOOTING(1)
The drum motor fails to run.
Is the voltage more than about 2.6V
DC given out of pin(30) of IC701?
YES
Is the voltage more than about 2.6V
DC given out of pin(12) of P701?
YES
Is the supply voltage of 12V fed to
pin(8) of P701?
YES
Replace drum motor.
Check AT 5V line.
Check pin(38), (39) of IC8001
and peripheral circuits.
NO
Check peripheral circuit of pin(41)
of IC8001.
NO
Replace IC8001.
NO
Check IC701.
Check line between pin(30) of IC701
NO
and pin(12) of P701.
NO
Check M 12V line.
FLOW CHART NO.15 DRUM MOTOR TROUBLESHOOTING(2)
Is drum PG signal given out from the
pin (11) of P701?
Is drum PG signal fed to pin(65) of
IC701?
Is head switching pulse sent out from
the pin(23) of IC701?
Replace IC701.
FLOW CHART NO.16 HEAD SWITCHING PULSE TROUBLESHOOTING.
Is the drum motor rotating?
Is the drum PG signal and drum FG
signal present at pin(65) of IC701?
NO
D-PG
D-FG
Are the drum PG signal and drum FG
signal present on pin(11) of P701?
NO
Check peripheral circuit of IC on
mechanism.
Digitized in Heiloo the Netherlands
The drum motor runs only for a few seconds.
Check peripheral circuit of IC on
NO
mechanism
YES
NO Check line between pin(11) of P701
and pin(65) of IC701.
YES
NO
YES
No head switching pulse.
See FLOW CHART NO.14, 15 (DRUM
NO
MOTOR TROUBLESHOOTING(1), (2))
YES
YES
2.5V
2.5V
YES
Check line between P701 and
IC701.
6/17/2019
Replace IC on mechanism.
NO
YES
Check drum motor.
Check IC701.
Replace IC701.
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