25
HCD-GNZ77D/GNZ88D
0 dB=0.775 V
DECK SECTION
1. Demagnetize the record/playback head with a head
demagnetizer.
2. Do not use a magnetized screwdriver for the adjustments.
3. After the adjustments, apply suitable locking compound to the
parts adjust.
4. The adjustments should be performed with the rated power
supply voltage unless otherwise noted.
5. The adjustments should be performed in the order given in this
service manual. (As a general rule, playback circuit adjustment
should be completed before performing recording circuit
adjustment.)
6. The adjustments should be performed for both L-CH and R-
CH.
7. Switches and controls should be set as follows unless otherwise
specified.
• Test Tape
Record/Playback Head Azimuth Adjustment
Note:
Perform this adjustments for both decks
Procedure:
1. Mode: Playback
Tape
Signal
Used for
P-4-A063
6.3 kHz, –10 dB
Azimuth Adjustment
DECK A DECK B
3. Mode: Playback
4. After the adjustments, apply suitable locking compound to the
pats adjusted.
Adjustment Location: Playback Head (Deck A).
Record/Playback/Erase Head (Deck B).
set
MAIN board
IC101
Pin 28 (L-CH)
Pin 37 (R-CH)
MAIN board
IC101
Pin 36 (GND)
+
–
level meter
test tape
P-4-A063
(6.3 kHz, –10 dB)
MAIN
board
IC101
test tape
P-4-A063
(6.3 kHz, –10 dB)
pin 37
oscilloscope
L-CH
R-CH
V
H
waveform of oscilloscope
in phase 45
°
90
°
135
°
180
°
good
wrong
pin 36
pin 28
L
R
forward
forward
2. Turn the adjustment screw and check output peaks. If the peaks
do not match for L-CH and R-CH, turn the adjustment screw
so that outputs match within 1dB of peak.
L-CH
peak
R-CH
peak
within
1dB
screw
position
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