Tape Speed Adjustment - Sony HCD-XB4 Service Manual

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 (FWD)
test tape
P-4-A100
(10kHz, –10dB)
pin 1
L-CH
main
L
board
CN207
R
set
R-CH
pin 3
waveform of oscilloscope
in phase 45 °
good
4. Repeat steps 1 to 3 in playback (REV) mode.
5. After the adjustments, apply suitable locking compound to the
pats adjusted.
Adjustment Location: Record/Playback Head (Deck A and B)
and main board.
forward
within
1dB
Screw
angle
R-CH
peak
oscilloscope
pin 2
V H
90 ° 135 ° 180 °
wrong
reverse
Tape Speed Adjustment DECK A
Note: Start the Tape Speed adjustment as below after setting to the
test mode.
In the test mode, the tape speed is high during pressing the
H. SPEED DUBB button.
Procedure:
1. Turn the power switch on.
2. Press the GROOVE button, ENTER/NEXT button and
DISC 4 button simultaneously.
To exit from the test mode, press the POWER button.
Mode: Playback (FWD)
test tape
WS-48B
(3 kHz, 0 dB)
1. Insert the WS-48B into the deck A and the blank tape into the
deck B.
2. Press the REC button and · button on the deck B. Then
the deck B is at recording mode.
3. Set the deck A to playback mode.
4. Keep pressing the H. SPEED DUBB button in playback mode.
Then at HIGH speed mode.
5. Adjust RV652 on the AUDIO board do that frequency counter
reads 6,000 ± 60 Hz.
6. Take off the H. SPEED DUBB button.
Then at NORMAL speed mode.
7. Adjust RV651 on the AUDIO board so that frequency counter
+ 30
reads 3,000 Hz.
– 10
8. Frequency difference between deck A and deck B the beginning
of the tape should be within ± 1.5%.
Adjustment Location: AUDIO board
Playback level Adjustment DECK A
Procedure:
Mode: Playback (FWD)
test tape
P-4L300
(315 Hz, 0 dB)
set
Deck A is RV311 (L-CH) and RV411 (R-CH), Deck B is RV301 (L-
CH) and RV401 (R-CH) so that adjustment within adjustment level
as follows.
Adjustment Level:
CN207 PB 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 and main boards
– 32 –
+
set
–
main board
CN (Pin 1 : L-CH)
(Pin 3 :R-CH)
DECK B
level meter
+
–
main board
CN207 (Pin 1 : L-CH)
(Pin 3 : R-CH)