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5.
ELECTRICAL
ADJUSTMENTS
Precautions
for
Adjustment
and
Measuremen
_t
1.
Before playing back
the
test
tape, thoroughly demag-
netize
the
heads, capstan and similar metal parts using
an erase, as
the
test
tape-recorded
tone
is
easily erased.
2. Do
not
place
the
test
tape
on
any measuring instrument.
3.
Do
not
put
the
test
tape
near a place where
the
eraser
is
used.
4.
Method of Demagnetization: Turn
the
eraser power
..
switch
on
at a position far away from
the
heads. Bring
the
eraser close
to
the
heads, capstan and
other
parts
to
be demagnetized, and move it
up
and down four
or
five
times
to
demagnetize. Slowly separate
the
eraser far
away from
the
parts, and
turn
the
power switch off.
5.
Do
not
use any magnetized adjusting tool.
If
necessary,
demagnetize with a bulk eraser from time
to
time
in
the
course
of
each adjustment.
6.
Do
not
turn
semi-fixed resistor
or
coil more
than
needed.
7. Measure speed and wow and flutter
in
the
normal
operating state.
8.
Do
not
apply locking bond excessively.
9. Check
the
line voltage and
the
output
of low frequency
oscillator 2 - 3 times a day
to
see
if
they
are set
as
specified.
5.1
Head Azimuth Adjustment
1. Play
the
test
tape MTT256 back. Adjust the head azimuth
adjusting screw for maximum VTVM reading.
2. If the peak levels
of
the
left and right channels are
different set
the
screws
to
obtain
the
mechanical
center
between
the
peaks.
3. After adjustment, repeat
the
playback and
stop
settings
several times
to
confirm no azimuth deviation.
4. After adjustment, lock
the
screws with bond.
5.2
Mode: Playback
Test Tape
MTT-256
14kHz
~
Unh
Tape
Speed
Adjustment
VTVM
1. Play
the
3kHz signal
of
the
test
tape
MTT· 111 back.
2. Adjust
the
adjusting resistor (RM05)
on
the
P600
P.W.
Board so
that
counter
readings are between
2990
-
3010Hz.
Mode: Playback
Test Tape
MTT-111
3 kHz
Unit
Line
Output
Frequency
Counter
I
000000
1
3
5.3
Playback
Equalizer
Adjustment
1. Adjust
the
tape
selector switch
to
NORMAL.
2. Play
the
315Hz signal
of
the
test
tape
MTT-256 back.
The VTVM
at
0dB.
3. Play
the
12.5kHz signal of
the
test
tape
back. Confirm a
frequency response
of
Oto
ldB
in
reference
to
the
315Hz
signal level.
5.4
Then, play
the
12.5kHz signal back.
Set
the
tape
selector
to
CrO
2
,
Metal. Confirm
the
12.5kHz signal readings
at
- 4.5dB, ±1dB.
Mode: Playback
Test Tape
MTT-256
14 kHz
Playback
Level
Adjustment
VTVM
ldl
1.
Adjust
the
Tape Selector Switch
to
NORMAL and
turn
the
NR
switch
OFF.
2. Play
the
test
tape MTT-150 back. Adjust R110(L) and
R210(R) so
that
the
voltage
of
OA02
@pin
and
@pin
is
100mV.
In
this operation, make sure
the
voltage
of
LINE
OUT
reads 550mV +
ldB.
NOTES:
1.
Proceed
both
for
the
night
and
left channels in
the
same
way.
2. For details refer
to
"Playback equalizer
adjustment".
Mode:
Palyback
Test Tape
MTT-150
0A02
@@
Pin
5.5 Level Meter Adjustment
VTVM
ldl
1. Adjust
the
Tape Selector Switch
to
NORMAL and
turn
the
NR
switch OFF.
2. Play
the
test
tape
MTT-150 back. Adjust R 128(
L)
and
R228(R)
at
+3dB Level Meter reading.
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