Read Sharp VC-MH834 (serv.man3) Service Manual online
43
VC-M314HM
VC-MH834HM
VC-MH834HM
YES
YES
YES
NO
NO
NO
FLOW CHART NO.1
1 SYSTEM CONTROL
TROUBLESHOOTING
No power is turned on.
Does power control (H) signal at
pin(94) of IC701 change from "L" to
"H" level?
Check IC701.
Does the base voltage of Q9904 or
Q9951 change from about 12.6V to
11.8V?
Check line between Q9904 or
Q9951, Q9905 and IC701.
Is voltage of 12V sent out from the
emitter of Q9904 or Q9951 transistor?
Check peripheral circuit of Q9904
or Q9951 and
A
T
12V line.
YES
YES
YES
NO
NO
Does the base voltage of Q9903
change from about 5.5V to 6.2V?
Check line between emitter of Q9904
or Q9951 and base of Q9903.
Is voltage of 5V sent out from the
emitter of Q9903 transistor?
Check peripheral circuit of Q9903
and
A
T
5V line.
Check peripheral circuit for poor
soldering.
NO
NO
NO
FLOW CHART NO.9 CASSETTE CONTROL
TROUBLESHOOTING(2)
A
cassette tape is taken in, but ejected at once.
Does the start sensor pulse at pin(79)
of IC701 change from "L" to "H" level
when the cassette tape is loaded?
Check line between start sensor
and pin(79) of IC701.
Does the end sensor pulse at pin(85)
of IC701 change from "L" to "H" level
when the cassette tape is loaded?
Check line between end sensor
and pin(85) of IC701.
Does the master cam mode
shifter operate normally when the
cassette tape is loaded?
Check line between cam switch
and IC701.
Replace IC701.
YES
YES
YES
FLOW CHART NO.10 LOADING MOT
OR
AND EJECT TROUBLESHOOTING
The cassette tape fails to come out.
Does the capstan motor start when
the EJECT
button is pressed?
See FLOW CHAR
T
NO.12
CAPST
AN MOT
OR
TROUBLE-
SHOOTING
Does the take-up reel disk turn
when the capstan motor is running?
Check line between take-up reel
sensor and pin(2) of IC701.
Is a "H" level applied at pin(12)
of IC7002 when a reel pulse has
been inputted?
Check line between pin(92) of
IC701 and pin(12) of IC7002.
Is the supply voltage of 12V fed
to pin(9) of IC7002?
Is the voltage about 10V sent out
from pin(15) of IC7002?
Check IC7002.
Is the specified voltage applied at
the loading motor terminal?
Check line between IC7002 and
loading motor
.
Does the loading motor run?
Replace cassette cam, gear
, etc.
YES
YES
YES
Check M 12V lines.
NO
YES
NO
YES
YES
YES
NO
NO
NO
NO
NO
Replace loading motor
.
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