21
HCD-GN700/GX8800
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.
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).
REC BIAS ADJUSTMENT DECK B
Procedure:
In the MC test mode, the “REC memory mode” is convenient for
this adjustment. In the “REC memory mode” , when the REC starts
the input signal FUNCTION is switched to VIDEO automatically.
When the REC stops, the tape returns near to the recording start
position.
1. Press
MD (VIDEO)
button to select VIDEO. (This step is not
necessary if the above test mode has already been set)
2. Insert a tape into deck B.
3. After press
[REC PAUSE/START]
button, press
[REC PAUSE/
START]
button, then recording start.
4. Mode: Record
5. Mode: Playback
6. Confirm the playback signal recorded in step 3 becomes
adjustable level as follows.
If these levels are not adjustable level, adjust the RV304 (L-
CH) and RV354 (R-CH) on the MAIN board to repeat steps 4
and 5.
Adjustable level: Playback output of 315 Hz to playback output
of 10 kHz:
±
1.0 dB
Adjustment Location: MAIN board
Screw
position
L-CH
peak
within
1dB
Output
level
L-CH
peak
R-CH
peak
within
1dB
Screw
position
R-CH
peak
MAIN
board
CN301
set
test tape
P-4-A100
(10 kHz, –10 dB)
pin
3
oscilloscope
L-CH
R-CH
V
H
waveform of oscilloscope
in phase 45
°
90
°
135
°
180
°
good
wrong
pin
2
pin
1
L
R
attenuator
set
MAIN board
MD/VIDEO (AUDIO) IN (J750)
1) 315 Hz
2) 10 kHz
50 mV (–23.8 dB)
600
Ω
blank tape
CN-123
AF OSC
+
–
set
recorded
portion
MAIN board
CN301 Pin
2
(GND)
MAIN board
CN301
Pin
1
(L-CH)
Pin
3
(R-CH)
level meter
forward
reverse
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