Electrical Adjustments; Deck Section; Check - Sony HCD-F250AV Service Manual

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3 7 63 1515 0

DECK SECTION

1. Demagnetize the record/playback head with a head
demagnetizer.
2. Do not use a magnetized screwdriver for the adjustments.
3. After the adjustments, apply suitable locking compound to the
parts adjust.
4. The adjustments should be performed with the rated power
supply voltage unless otherwise noted.
5. The adjustments should be performed in the order given in this
service manual. (As a general rule, playback circuit adjustment
should be completed before performing recording circuit
adjustment.)
6. The adjustments should be performed for both L-CH and R-
CH.
7. Switches and controls should be set as follows unless otherwise
specified.
• Test Tape
Tape
P-4-A100 10 kHz, –10 dB
WS-48B
P-4-L300
Record/Playback Head Azimuth Adjustment
DECK A DECK B
Note: Perform this adjustments for both decks
TE
Procedure:
L 13942296513
1. Mode: Playback
test tape
P-4-A100
(10 kHz, –10 dB)
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ELECTRICAL ADJUSTMENTS

0 dB=0.775 V
Signal Used for
Azimuth Adjustment
3 kHz, 0 dB Tape Speed Adjustment
315 Hz, 0 dB Level Adjustment
main board
CN301
Pin 3 (L-CH)
Pin 1 (R-CH)
level meter
set
+
–
main board
CN301
Pin 2 (GND)
x ao
y
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SECTION 5
8
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
Screw
position
3. Mode: Playback
test tape
P-4-A100
(10 kHz, –10 dB)
Q Q
3 6 7 1 3
4. After the adjustments, apply suitable locking compound to the
pats adjusted.
Adjustment Location: Playback Head (Deck A).
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.
— 21 —
2 9 9 4 2 8
within
1dB
Output
level
R-CH
peak
L-CH
R-CH
peak peak
oscilloscope
pin 3
L-CH
pin 2
MAIN
L
board
CN301
R
set
R-CH
pin 1
waveform of oscilloscope
1 5 0 5 8 2 9 9 4
in phase 45 ° 90 ° 135 ° 180 °
wrong
good
Record/Playback/Erase Head (Deck B).
m
co
9 9
within
1dB
Screw
position
V H
2 8 9 9