Sony HCD-GN700 Service Manual page 21

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.
within
L-CH
1dB
peak
Output
level
R-CH
peak
Screw
position
L-CH
peak
3. Mode: Playback
test tape
P-4-A100
(10 kHz, –10 dB)
pin 1
L-CH
MAIN
L
board
CN301
R
set
R-CH
pin 3
waveform of oscilloscope
in phase 45 °
good
4. After the adjustments, apply suitable locking compound to the
pats adjusted.
Adjustment Location: Playback Head (Deck A).
Record/Playback/Erase Head (Deck B).
forward
within
1dB
Screw
position
R-CH
peak
oscilloscope
pin 2
V H
90 ° 135 ° 180 °
wrong
reverse
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 button to select VIDEO. (This step is not
MD (VIDEO)
necessary if the above test mode has already been set)
2. Insert a tape into deck B.
[REC PAUSE/START]
3. After press
START]
button, then recording start.
4. Mode: Record
MAIN board
MD/VIDEO (AUDIO) IN (J750)

1) 315 Hz

2) 10 kHz

AF OSC
600 Ω
attenuator
5. Mode: Playback
MAIN board
CN301
recorded
Pin 1 (L-CH)
portion
Pin 3 (R-CH)
set
MAIN board
CN301 Pin 2 (GND)
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
HCD-GN700/GX8800
[REC PAUSE/
button, press
50 mV (–23.8 dB)
blank tape
CN-123
set
level meter
+
–
21