Read Sharp VC-MH75 (serv.man8) Service Manual online
37
VC-MH75HM
MECHANISM TROUBLESHOOTING
1. FF/REW FAILURE (NO TAPE WINDING)
Press FF key.
NO
NO
NO
NO
NO
NO
NO
NO
YES
YES
YES
YES
YES
YES
YES
YES
Is master cam at
FF position ?
FF position ?
Does loading
motor operate ?
motor operate ?
Modes changing
smoothly through
mode switch ?
smoothly through
mode switch ?
Loading motor
control system
in trouble.
control system
in trouble.
Are Vco 24V and
Vcc 5V applied ?
Vcc 5V applied ?
Replace the
capstan motor.
capstan motor.
Replace the idler
ass’y.
ass’y.
Replace the reel
sensor.
sensor.
Is voltage applied
to loading motor ?
to loading motor ?
Loading motor is
damaged. Replace
it.
damaged. Replace
it.
Voltage supply
system in trouble.
system in trouble.
Mode SW in
trouble or master
cam malpositioned.
trouble or master
cam malpositioned.
Voltage supply
system in trouble.
system in trouble.
Does capstan
motor turn in FF (or
REW) direction ?
motor turn in FF (or
REW) direction ?
Are idler wheel
ass’y and reel disk
in mesh ?
ass’y and reel disk
in mesh ?
Is the pulse
outputted from reel
sensor ?
outputted from reel
sensor ?
The cassette tape
is presumably
damaged.
is presumably
damaged.
2. REC/PLAY FAILURE (MODE RELEASE)
NO
NO
NO
NO
NO
NO
NO
YES
YES
YES
YES
YES
YES
YES
YES
Is the master cam
at PB position ?
at PB position ?
Does loading
motor operate ?
motor operate ?
Modes changing
smoothly through
mode switch ?
smoothly through
mode switch ?
Loading motor
control system
in trouble.
control system
in trouble.
Are Vco 24V and
Vcc 5V applied ?
Vcc 5V applied ?
Replace the
capstan motor.
capstan motor.
Replace the idler
ass’y.
ass’y.
Replace the reel
sensor.
sensor.
Is voltage applied
to loading motor ?
to loading motor ?
Loading motor is
damaged. Replace
it.
damaged. Replace
it.
Voltage supply
system in trouble.
system in trouble.
Voltage supply
system in trouble.
system in trouble.
Does capstan
motor turn ?
motor turn ?
Are idler wheel
ass'y and reel disk
in mesh ?
ass'y and reel disk
in mesh ?
Is the pulse
outputted from reel
sensor ?
outputted from reel
sensor ?
Check main PWB.
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