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'D-W20A/B/C/E/G/J/U
Main Adjustments
1) Electronic voltmeter
2) Audio
frequency
oscillator
(range; 50-20 kHz
and
output
0 dB with impedance of 600 22)
Maxell UD
—
Normal (SF) tape —
TDKSA
— Chrome (SA) tape
—or equivalent
JVC ME
— Metal tape
VTT64
VTT73
ter adj.)
4 (or VTT724) (for playback level)
9 (for playback frequency response)
TMT7008 (14 kHz) (for head azimuth adj.)
2. Mecha
Adjusting
motor speed
Checking
wow and
flutter
torque
Checking
fast forward
torque
| Checking re-
wind torque
nism adjustment proceder
6) Resistor 600 Q (for attenuator matching)
7) Distortion meter (bandpass filter)
8) Torque testing cassette gauge, CGT-N
9) Wow flutter meter
10) Frequency counter
* Adjustment
1, Connect a frequency counter to the
LINE OUT terminals.
2. Play back the TMT6451
(or VTT-
655A) test tape.
3. Adjust for deck{A]:
Adjust VRMO3 for normal
speed at
3000 Hz, and VRMO1 for high speed
at 6000 Hz.
Adjust for deck([B]:
Adjust VRM04 for normal! speed at
3000Hz, and VRMO2 for high speed
at 6000 Hz.
Connect
a wow
and flutter meter to
LINE
OUT
terminals.
Play back
the
TMT6451
(or VTT656A)
test tape.
Check
to see
if the
reading
of the
eter is within 0.08% (WRMS)
m
.
Checking
Employ a torque testing cassette tape
playback
for the checking,
or remove
the cas-
sette cover and use a torque gauge.
Remarks
For
adjusting high speed, HI-SPEED
test point should be grounded.
Adjust
high
speed
after
perform
normal
speed.
If the reading becomes
moving value
even if confirming to the standard, a
re-claim
may
be raised.
Repairs
are
necessary.
If the standard torque is not obtained,
replace the take-up disk assembly.
Measure the torque in the fast forward
mode
in the same
manner
as in the
above.
Measure the torque in the rewind mode
in the same manner as in the above.
fis
8 (No. 4256)
Adjusting
Standard
point
value
Deck[A]: | Normal speed:
Normal;
Deck [Al;
VRMO3
3000 Hz
High;
Deck|B];
VRMO1
3000 Hz
Deck(B]: | High speed:
Normal;
Deck|A|;
VRMO4
6000
Hz
High;
Deck({B/;
VRMO2
6000 Hz
0.08% (WRMS)
0.2%
(DIN 45500)
35-75 gr-cm
More than
70 gr-cm
More than
70 gr-cm
If the standard torque is not obtained,
perform the following.
1. Clean the capstan belt, the idler cir-
cumference,
the motor
pulley, the
take-up reel disk circumference, the
flywheel circumference, etc.
2. Replace the belt and idler.
If the standard torque is not obtained,
clean the capstan belt, idler, motor pul-
ley, flywheel circumference, rewinding
idler circumference,
left reel disk cir-
cumference, etc.
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