JVC KD-21 - Page 11

KD-21A/B/E/U
KD-15A/B/C/E/J/U
Trouble
Shooting
Guide
[ELECTRICAL
CIRCUIT]
2.
If
found
poor,
check
the
wiring
of
the
recording
1.
Playback
tone
quality
is
poor.
system
for
a
broken
wire
and
short-circuit.
1.
Check
the
record/playback
head
for
dust.
3.
If
no
irregularity
is
found,
check
the
recording
bias
2.
Check
the
record/playback
head
for
wear.
current.
Also
check
the
oscillation
circuit.
If
worn
excessively,
the
loss
of
treble
response
will
3.
For
other
failures,
check
the
unit
in
the
same
manner
as
result.
other
amplifiers.
3. Check wiring for a short-circuit.
Check each transistor for condition.
5:
Recording
tone:quelity
is
poor
[MECHANISM
SECTION]
(wow
and
flutter)
The
playback
tone
quality
of
a
recorded
tape
such
as
the
If
wow
and
flutter
increase,
check
the
following
points.
audition
tape
is
good,
but
the
recording
by
this
unit
lf
there
is
defect
in
revolving
parts,
the
wow
and
flutter
produces
poor
tone
quality.
In
this
case,
the
unit
should
generated
will
increase
in
proportion
to
the
number
of
be checked in the following manner. revolutions.
1.
By
monitoring
a
music
while
recording,
check
the
Play
a
3000Hz
test
tape,
and
defective
part
can
be
detected
tone
quality.
from
the
sound.
Capstan shaft has excessive run-out.
Flywheel turns heavily.
(shaft seisure, thrust play, etc.)
Capstan
and
Replace
flywheel.
Clean the capstan shaft and the groove in the
flywheel.
Apply oil to the metal position.
Replace the capstan assembly.
Rough rotation (Deformation scratches,
or dust).
The angular position of the pinch
roller is not correct.
The pinch roller pressure is not correct.
flywheel
Replace pinch roller, or pinch roller spring.
Clean the pinch roller or apply oil to the rotary
shaft.
Adjust the pinch roller so that it is parallel with
the capstan shaft.
Pinch roller
Replace the pinch roller spring.
Belt
Belt
has
undue
run-out.
Clean
the
belt
or
remove
the
distortion.
Belt
is
dirty
or
slippery.
Replace
the
belt.
Back
tension
Back
tension
is
irregular,
or
back
Replace
back
tension
spring
(under
supply
disc).
tension
is
too
strong.
Motor
Motor
shaft
has
undue
run-out.
Replace
motor.
Motor
pulley
is
oily
and
dusty.
Clean
motor
pulley.
Take-up
idler
arm
Pulley
has
deflection.
Replace
take-up
idler
arm.
Pulley
is
stuck.
—11- No. 4150