Read Sharp VC-M303 (serv.man9) Service Manual online
41
FLOW CHART NO.12 CAPSTAN MOTOR TROUBLESHOOTING
The capstan motor fails to run.
Is the voltage more than about 2.6V
DC given out of pin(59) of IC701?
Check IC701.
NO
NO
NO
NO
NO
YES
YES
YES
YES
Is the supply voltage of 5V fed to
pin(8) of AC connector?
Check PC 5V line.
Is the voltage more than 2.6V DC
sent in pin(4) of AC connector?
Check line between the AC connector
and pin(59) of IC701?
Is the voltage of pin(3) of AC
connector 1.6~2.7V?
Check line between the pin(60) of
IC701 and pin(3) of AC connector.
Is the supply voltage of 12V/20V fed
to pin(5) of AC connector?
YES
Replace capstan motor.
Check MOTOR Vcc line and motor
voltage selector circuit.
(Q9903, 9904, 9909, 9910)
FLOW CHART NO.13 DRUM MOTOR TROUBLESHOOTING(1)
The drum motor fails to run.
Is the voltage more than about 2.6V
DC given out of pin(58) of IC701?
Check IC701.
NO
NO
NO
YES
YES
Check PC 5V and line and pin(9)
of IC701.
Is the supply voltage of 5V fed to
pins(25) and (2) of IC702?
Is the voltage more than about 2.6V
DC given out of pin(29) of IC702?
Check line between pin(58) of IC701
and pin(29) of IC702.
NO
YES
YES
Is the supply voltage of 12V fed to
pin(20) of IC702?
Replace drum motor.
Check M 12V line.
FLOW CHART NO.14 DRUM MOTOR TROUBLESHOOTING(2)
The drum motor runs only for a few seconds.
Replace IC702.
Check peripheral circuit of pins(4),
(5), (6) and (7) of IC702.
Is drum PG signal given out from the
pin(8) of IC702?
Is drum PG signal fed to pin(66) of
IC701?
Check line between pin(8) of IC702
and pin(66) of IC701.
Is head switching pulse sent out
from the pin(23) of IC701?
Check IC701.
Replace IC701.
NO
Check drum motor.
YES
YES
YES
YES
NO
NO
NO
D-FG
about 5Vp-p
D-PG
about 5Vp-p
YES
NO
YES
YES
NO
NO
FLOW CHART NO.15 HEAD SWITCHING PULSE TROUBLESHOOTING.
No head switching pulse.
See FLOW CHART NO.13, 14
(DRUM MOTOR
TROUBLESHOOTING(1), (2))
Is the drum motor rotating?
Is the drum PG signal and drum
FG signal present on pins(66) and
(65) of IC701, respectively?
Replace IC701.
Check line between IC702 and
IC701.
Check peripheral circuit of IC702.
Are the drum PG signal and drum
FG signal present on pins (8), (9)
of IC702?
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