HCD-XB88AVK, HCD-XB88K, LBT-XB88AVK, LBT-XB88KS - Sony Audio Service Manual (repair manual). Page 13

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4. After the adjustments, apply suitable locking compound to the

parts adjusted.

Adjustment Location: Playback Head (Deck A)

Record/Playback/Erase Head (Deck B)

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 1 dB of peak.

3. Mode: Playback

Note: Set the test mode using the following method and begin tape

speed adjustment.
In the test mode, the tape will move at double speed or normal
speed each time the  H SPEED DUB.  button is pressed.

Procedure :
With the power turned ON, press the  SPECTRUM ANALYZER
button,  ENTER  button, and  EFFECT  button simultaneously.
(The “VOLUME” on the fluorescent display tube will blink while
in the test mode.)
To exit the test mode, press the  1/u  button.

1. Load WS-48B into deck B.
2. Play deck B.
3. Press the  H SPEED DUB.  button and play the tape at double

speed.

4. Adjust RV652 of the AUDIO board so that the reading of the

frequency counter becomes 6000 ± 180 Hz.

5. Press the  H SPEED DUB.  button and play the tape at normal

speed.

6. Adjust RV651 of the AUDIO board so that the reading of the

frequency counter becomes 3000 ± 90 Hz.

Adjustment Location: AUDIO board

W.RMS (JIS) less than 0.3%
(test tape: WS-48B)

Procedure:
Mode: Playback

Deck A is RV311 (L-CH) and RV411 (R-CH), deck B is RV301
(L-CH) and RV401 (R-CH)
so that adjustment within the following adjustment level.

Adjustment level:
CN403 playback level: 301.5 to 338.3 mV (–8.2 to –7.2 dB)
level difference between the channels: within ± 0.5 dB
Adjustment Location: AUDIO board

L-CH
peak

R-CH
peak

screw
position

output
level

within
1 dB

L-CH
peak

R-CH
peak

screw
position

within 1dB

test tape
P-4-A100
(10kHz, –10dB)

oscilloscope

set

L

R

Waveform of oscilloscope

in phase

45

°

90

°

135

°

180

°

good

wrong

main board
CN403
Pin 

3

 (L-CH)

Pin 

2

 (GND)

Pin 

1

 (R-CH)

reverse

forward

test tape 
P-4-L300
(315Hz, 0dB)

level meter

set

main board
CN403

Pin 

3

 (L-CH)

Pin 

1

 (R-CH)