Sony HD-XB4K Service Manual page 33

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1. Mode: Playback (FWD)
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.
L-CH
peak
output
level
R-CH
peak
Screw
position
3. Mode: Playback (FWD)
test tape
P-4-A100
(10kHz, –10dB)
L-CH
MAIN
board
CN207
set
R-CH
TE
L 13942296513
in phase 45 °
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)
forward
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within
1dB
L-CH R-CH
peak
peak
oscilloscope
pin 1
pin 2
L
V H
R
pin 3
waveform of oscilloscope
90 ° 135 ° 180 °
wrong
good
and MAIN board.
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8
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 SPECTRUM ANALYZER button, ENTER button
and EFFECT button simultaneously.
within
To exit from the test mode, press the POWER button.
1dB
Mode: Playback (FWD)
test tape
WS-48B
(3 kHz, 0 dB)
Screw
position
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 ± 90 Hz.
6. Take off the H. SPEED DUBB button.
Q Q
3 6 7 Then at NORMAL speed mode. 1 3
7. Adjust RV651 on the AUDIO board so that frequency counter
reads 3,000 ± 90 Hz.
8. Frequency difference between deck A and deck B the begin-
ning of the tape should be within ± 1.5%.
Adjustment Location: AUDIO board
Sample Value of Wow and flutter: 0.3% or less W.RMS
Playback level Adjustment DECK A
Procedure:
Mode: Playback (FWD)
test tape
P-4-L300
(315 Hz, 0 dB)
reverse
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
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2 9 9 4 2 8
frequency counter
set
MAIN board
CN207 (Pin 1 : L-CH)
(Pin 3 : R-CH)
1 5 0 5 8 2 9 9 4
(WS-48B)
level meter
set
MAIN board
CN207 (Pin 1 : L-CH)
(Pin 3 : R-CH)
m
co
9 9
+
–
2 8 9 9
DECK B
+
–