Electrical Adjustments - Sony HCD-GTX88 Service Manual

HCD-GTX88
0 dB = 1 µV
TUNER SECTION
[FM Tune Level Check]
SET
Procedure:
1. Turn the power on.
2. Input the following signal from Signal Generator to FM
antenna input directly.
* Carrier Freq : A = 87.5 MHz, B = 98 MHz, C = 108 MHz
Deviation : 75 kHz
Modulation : 1 kHz
ANT input : 35 dBu (EMF)
Note: Please use 75 ohm "coaxial cable" to connect SG and the set. You
cannot use video cable for checking.
Please use SG whose output impedance is 75 ohm.
3. Set to FM tuner function and tune A, B and C signals.
4. Confirm "TUNED" is lit on the display for A, B and C signals.
The mark of "TUNED" means "The selected station signal is
received in good condition."
28
SECTION 5

ELECTRICAL ADJUSTMENTS

FM signal generator
OUT (75 Ω )
[RECORD/PLAYBACK HEAD AZIMUTH
ADJUST-MENT]
Note: Perform this adjustments for both decks
Procedure:
0 dB = 0.775 V
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 Signal
P-4-A100 10 kHz, –10 dB
DECK A DECK B
1. Mode: Playback
test tape
MAIN board
P-4-A100
CN510
(10 kHz, –10 dB)
Pin 1 (L-CH)
Pin 3 (R-CH)
set
MAIN board
CN510
Pin 2 (GND)
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
Used for
Azimuth Adjustment
level meter
+
–
within
1dB
screw
position
L-CH
R-CH
peak
peak