Sony HCD-GP7 Service Manual page 18

HCD-GP7
QQ
3 7 63 1515 0
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 4
L-CH
MAIN
L
board
CN302
R
set
R-CH
pin 6
waveform of oscilloscope
TE
L 13942296513
in phase 45 °
good
4. Repeat step 1 to 3 in playback (REV) mode.
5. After the adjustments, apply suitable locking compound to the
pats adjusted.
Adjustment Location: Record/Playback/Erase Head.
www
forward
.
18
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within
1dB
Screw
position
R-CH
peak
oscilloscope
pin 2
V H
90 ° 135 ° 180 °
wrong
x ao
y
reverse
i
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8
[Rec Bias Adjustment]
Procedure:
In the common test mode, the "Tape test mode" is convenient for
this adjustment. In the "Tape test mode", when the REC starts the
input signal FUNCTION is switched to MD automatically.
When the REC stops, the tape returns near to the recording start
position.
1. Press MD (VIDEO) button to select MD. (This step is not
necessary if the above test mode has already been set)
2. Insert a tape into deck B.
3. After press z REC PAUSE/START button, press z REC
PAUSE/START button, then recording start.
4. Mode: Record
MAIN board
MD (VIDEO)(J301)
1) 315 Hz
2) 10 kHz
AF OSC
attenuator
5. Mode: Playback
recorded
portion
Q Q
3 6 7 1 3
6. Confirm the playback signal recorded in step 3 becomes
adjustable level as follows.
If these levels are not adjustable level, adjust the RV653 (L-CH)
and RV603 (R-CH) on the TC 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: TC board & MAIN board
u163
.
2 9 9 4 2 8

50 mV (–23.8 dB)


blank tape
CN-123
600 Ω
set
MAIN board
CN302
level meter
Pin 4 (L-CH)
1 5 0 5 8 2 9 9 4
Pin 6 (R-CH)
+
set
–
MAIN board
CN302 Pin 2 (GND)
m
co
9 9
2 8 9 9