Sharp VC-MH705HM/LM Service Manual page 24

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FLOW CHART NO.10 CASSETTE CONTROL TROUBLESHOOTING(2)
A cassette tape is taken in, but ejected at once.
Does the start sensor pulse at pin (87)
of IC701 change from "L" to "H" level
when the cassette tape is loaded?
YES
Does the end sensor pulse at pin (86)
of IC701 change from "L" to "H" level
when the cassette tape is loaded?
YES
Does the master cam mode shifter
operate normally when the cassette
tape is loaded?
YES
Replace IC701.
FLOW CHART NO.11 LOADING MOTOR AND EJECT TROUBLESHOOTING
Does the capstan motor start when the
EJECT button is pressed?
YES
Does the take-up reel disk turn when the
capstan motor is running?
YES
Is a "H" level applied at pin(10) of P701
when a reel pulse has been inputted?
YES
Check IC on mechanism.
Is the voltage about 10V sent out from
IC on mechanism?
YES
Is the specified voltage applied at the
loading motor terminal?
YES
Does the loading motor run?
YES
Replace cassette cam, gear, etc.
Check line between start sensor and pin
NO
(87) of IC701.
NO Check line between end sensor and pin
(86) of IC701.
NO Check line between cam switch and
IC701.
The cassette tape fails to come out.
See FLOW CHART NO.12. CAPSTAN
NO
MOTOR TROUBLESHOOTING
Check line between take-up reel
NO
sensor and pin(2) of IC701.
NO
Check line between pin(92) of IC701
and pin(10) of P701.
Is the supply voltage of 12V fed to
NO
pin(8) of P701?
Check M 12V lines.
NO
Check line between IC on mechanism
and loading motor.
NO
Replace loading motor.
Digitized in Heiloo the Netherlands
FLOW CHART NO.12 CAPSTAN MOTOR TROUBLESHOOTING
Is the voltage more than about 2.6V
DC given out of pin(29) of IC701?
Is the supply voltage of 5V fed to
pin(3) of P701?
Is the voltage more than 2.6V DC
sent in pin(9) of P701?
Is the voltage of pin(5) of P701 is
1.6~2.7V?
Is the supply voltage of 12V/20V fed
to pin(2) of P701?
Replace capstan motor.
YES
NO
The capstan motor fails to run.
NO
YES
NO
YES
NO
Check line between pin(9) of P701
and pin(29) of IC701.
YES
NO
Check line between the pin(91) of
IC701 and pin(5) of P701.
YES
Check MOTOR Vcc line and motor
NO
voltage selector circuit.
YES
6/17/2019
Check IC701.
Check PC 5V line.
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