Read Sharp VC-MH85 (serv.man4) Service Manual online
44
VC-MH705HM/LM
VC-MH815HM/LM,MH85HM
VC-MH715HM,MH835HM
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?
DC given out of pin(30) of IC701?
Check IC701.
NO
NO
YES
Is the voltage more than about 2.6V
DC given out of pin(12) of P701?
DC given out of pin(12) of P701?
Check line between pin(30) of IC701
and pin(12) of P701.
and pin(12) of P701.
NO
YES
YES
Is the supply voltage of 12V fed to
pin(8) of P701?
pin(8) of P701?
Replace drum motor.
Check M 12V line.
FLOW CHART NO.15 DRUM MOTOR TROUBLESHOOTING(2)
The drum motor runs only for a few seconds.
Replace IC on mechanism.
Check peripheral circuit of IC on
mechanism
mechanism
Is drum PG signal given out from the
pin (11) of P701?
pin (11) of P701?
Is drum PG signal fed to pin(65) of
IC701?
IC701?
Check line between pin(11) of P701
and pin(65) of IC701.
and pin(65) of IC701.
Is head switching pulse sent out from
the pin(23) of IC701?
the pin(23) of IC701?
Check IC701.
Replace IC701.
NO
Check drum motor.
YES
YES
YES
YES
NO
NO
NO
D-FG
D-PG
YES
NO
YES
YES
NO
NO
FLOW CHART NO.16 HEAD SWITCHING PULSE TROUBLESHOOTING.
No head switching pulse.
See FLOW CHART NO.14, 15 (DRUM
MOTOR TROUBLESHOOTING(1), (2))
MOTOR TROUBLESHOOTING(1), (2))
Is the drum motor rotating?
Is the drum PG signal and drum FG
signal present at pin(65) of IC701?
signal present at pin(65) of IC701?
Replace IC701.
Check line between P701 and
IC701.
IC701.
Check peripheral circuit of IC on
mechanism.
mechanism.
Are the drum PG signal and drum FG
signal present on pin(11) of P701?
signal present on pin(11) of P701?
2.5V
2.5V
FLOW CHART NO.13 TIMER TROUBLESHOOTING
The LCD display fails to light up.
Is the supply voltage of 5V fed to
pin(37) of IC8001?
pin(37) of IC8001?
Check AT 5V line.
Is the supply voltage of 3.4V, 1.7V
feed to pin(38) and pin(39) of IC8001?
feed to pin(38) and pin(39) of IC8001?
Check pin(38), (39) of IC8001
and peripheral circuits.
and peripheral circuits.
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?
LCD RESET, LCD CS, LCD CLOCK
and LCD DATA on the pins(36),
(42), (43) and (44) of IC8001?
Are the segment signals
supplied to the LCD display
(LC8001) fromthe driver IC
(IC8001)?
supplied to the LCD display
(LC8001) fromthe driver IC
(IC8001)?
Check peripheral circuit of pin(41)
of IC8001.
of IC8001.
Check that the LCD display is
free from damages such as
crack.
free from damages such as
crack.
Replace IC8001.
YES
YES
YES
YES
NO
NO
NO
NO
NO
Check the signal line between
IC701 and IC8001.
IC701 and IC8001.
YES
Is the OSC signal at pin(41) of
IC8001 present?
IC8001 present?
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