Read Sharp VC-M303 (serv.man9) Service Manual online
40
FLOW CHART NO.10 LOADING MOTOR AND EJECT TROUBLESHOOTING
The cassette tape fails to come out.
Does the capstan motor start when
the EJECT button is pressed?
See FLOW CHART NO.12 CAPSTAN
MOTOR TROUBLESHOOTING
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(10) of
IC702 when a reel pulse has been
inputted?
Check line between pin(92) of IC701
and pin(10) of IC702.
Is the supply voltage of 12V fed to
pin(13) of IC702?
Is the voltage about 10V sent out
from pin(15) of IC702?
Check IC702.
Is the specified voltage applied at the
loading motor terminal?
Check line between IC702 and
loading motor.
Does the loading motor run?
Replace loading motor.
Replace cassette cam, gear, etc.
YES
YES
YES
Check M 12V lines.
NO
YES
NO
YES
YES
YES
NO
NO
NO
NO
NO
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 he cassette
tape is loaded?
Check line between cam switch and
IC701.
Replace IC701.
YES
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
FLOW CHART NO.11 SYSTEM CONTROL TROUBLESHOOTING
No power is turned on.
Are key data pulses applied at
pin(15) of IC701, respectively?
Check IC801 and IC701, and all the
way thru between them.
Are FIP data pulses, FIP clock pulses and FIP control ready pulses applied to pins(25), (24),
(23) and (22) of IC801, respectively?
Does power control (H) signal at
pin(94) of IC701 change from "L" to
"H" level?
Check IC701.
Does the base voltage of Q9905
change from about 9.3V to 10V?
Check line between Q9905, Q9906
and IC701.
Is voltage of 9V sent out from the
emitter of Q9905 transistor?
Check peripheral circuit of Q9905
and AT 12.8V line.
YES
YES
YES
NO
NO
Does the base voltage of Q9908
change from about 5.5V to 6.2V?
Check line between emitter of Q9905
and base of Q9908.
Is voltage of 5V sent out from the
emitter of Q9908 transistor?
Check peripheral circuit of Q9908
and AT 5V line.
Check peripheral circuit for poor
soldering.
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