Read Sharp VC-MH834 (serv.man3) Service Manual online
44
VC-M314HM
VC-MH834HM
VC-MH834HM
FLOW CHART NO.13 DRUM MOT
OR 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
.
Is the supply voltage of 5V fed to
pin(3) of IC7002?
Is the voltage more than about 2.6V
DC given out of pin(2) of IC7002?
Check line between pin(58) of
IC701 and pin(2) of IC7002.
NO
YES
YES
Is the supply voltage of 12V fed
to pin(21) of IC7002?
Replace drum motor
.
Check M 12V line.
FLOW CHART NO.12 CAPST
AN MOT
OR 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/25V fed
to pin(5) of
AC connector?
YES
Replace capstan motor
.
Check MOT
OR Vcc line and motor
voltage selector circuit.
(Q9507, Q9508, Q9904, Q9951)
FLOW CHART NO.14 DRUM MOT
OR TROUBLESHOOTING(2)
The drum motor runs only for a few seconds.
Replace IC7002.
Check peripheral circuit of pins
(4), (5), (6) and (7) of IC7002.
Is drum PG signal given out from
the pin(7) of IC7002?
Is drum PG signal fed to pin(66)
of IC701?
Check line between pin(7) of
IC7002 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 CHAR
T
NO.13, 14
(DRUM MOT
OR
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 IC7002
and IC701.
Check peripheral circuit of
IC7002.
Are the drum PG signal and drum
FG signal present on pins (7), (8)
of IC7002?
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