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Main Adjustments
Electrical Adjustment
Equipment and measuring instruments used for adjustment.
AUDIO Freq. OSC
1. V.T.V.M. (measuring AC in millivolt)
N cas
ATTENUATOR
2. Audio-frequency oscillator
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Jeep)
(range: 50—20kHz and output OdB with impedance 60022)
ae
By aS,
i 60002
DVO"
3. Attenuator
BOIS:
4. Reference tapes for REC/PB
pease
TS-1 (OP-12, C521V) — normal tape
by @
TS-2 (TP-18, C401R) — chrome tape
ouTPUT
LINE IN
5. Reference tapes for playback
VTT-664 (1kHz 16mM)
VTT-666 (400Hz 22mM)
6. Resistors
1002 (for measurement of the bias current)
6002 (for attenuator matching)
INPUT
LINE OUT
Fig. 7
When you adjust following item, we recommend to you to keep doing step No.
CA
1 Level meter
. Set the deck in the record mode.
(Main amp
The angle of meter deflection
Input 1KHz signals (about 10dBs) from
C. board
has been factory adjusted, but
LINE IN jacks and adjust LINE IN
TAA313201)
should be adjusted when parts
volume control so that LINE OUT are
are replaced.
-8dBs.
3. Adjust semi-fixed resistors R146 and
VR103,203
When adjust the level meter,
246 in this condition it obtain zero
don't use a headphone.
VU meter reading.
2 Peak level
. Set as same mode at step(1) and adjust
(Main amp
semi-fixed resistor R506 so that the
C. board
"0" indicator is lighting and no light-
TAA313201)
ing at -1dB from step(1) with atten-
R506
uator.
2. Adjust semi-fixed resistor R508 so that
the ''-5" indicator is lighting at -5dB
from step(1) with attenuator.
3. Adjust semi-fixed resistor R510 so that
the ""-10" indicator is lighting at -10dB
from step(1) with attenuator and no
lighting at -11dB from step(1) with
attenuator.
4. Adjust semi-fixed resistor R504 so that
the "+3" indicator is lighting at +3dB
from step(1) and no lighting at +2dB
from step(1) with attenuator.
5. Adjust semi-fixed resistor R502 so that
the "+6" indicator is lighting at +5dB
from step(1) with attenuator.
3 Playback
. Set equalizer switch at normal and
(Main amp
. Adjust playback sensitivity
sensitivity
playback reference tape
VT T-664.
C. board)
when heads are replaced.
Adjust semi-fixed resistors R115(L)
R115,215
2. Make this adjustment after
making sure level meter
deflection angle is correct.
and R215(R) so that level meters indi-
cate zero VU (about 0.3V at LINE
OUT).
2. Playback reference tape VTT-666 and
check that the VU meter indicate CAL.
CD-1770/A/B/C/E
No. 4144
2ghe
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