Troubleshooting - Sharp 27DV-S100 Service Manual

TROUBLESHOOTING

Mechanism malfunction.
MECHANISM
CONTROLLER (1)
Turn off AC power and get
the set restarted.
Does the AT5V line function?
Is there 14MHz oscillation at pins
(37) and (38) of IC2001?
The REC key does
No power is
not function. All the
supplied (PC5V).
other keys
function.
Turn on power. Is
Is the cassette
NO
the voltage at pin
tape without erase
(4) of IC2001 at
protection tag?
"H" level?
YES
Check
Is PC5V No recording can
NO
Q9101.
available? be made on
cassette tape
YES
without the tag.
Check the PC12V
line and PC23V
line.
Does the REC TIP
switch function?
Replace IC2001.
Replace the REC
TIP switch.
Replace IC2001.
NO
Check IC9021 and its peripheral circuits.
YES
NO
YES
The unit stops 3
seconds after
loading.
Is there the
NO NO
H.SW.P. output
signal at pin (23)
of IC2001?
YES
YES
Replace IC2001.
YES See Flowchart
No. 10.
NO
Is there the REC TIP
SW signal at pin (64)
of IC2001?
YES NO
Check the signal line.
Check IC2001 and X7001.
The pinch roller
The unit stops 5
fails to contact the
seconds after
capstan during
loading.
loading.
Is there the reel
Does the loading
NO
pulse input signal
motor stop after
at pins (2) and (3)
loading?
of IC2001?
YES
YES
Check the pinch
Replace IC2001.
roller pressure.
See Flowchart Check the cam
switches D7008
No. 11.
and D7009.
FLOW CHART No. 2-1
The FF or REW
The EJECT key
key does not
alone functions.
function.
NO
See Flowchart
NO A cassette tape is
No. 3.
inserted but pops
out itself.
See Flowchart
No. 2.