Read Sony HCD-GTX66 / HCD-GTX77 / HCD-GTX77BP / MHC-GTX66 / MHC-GTX77 / MHC-GTX77BP Service Manual online
28
HCD-GTX66/GTX77/GTX77BP
[FM Tune Level Check]
Procedure:
1. Turn the power on.
2. Input the following signal from Signal Generator to FM
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)
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.
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.
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.”
received in good condition.”
FM signal generator
OUT (75
Ω
)
SET
SECTION 5
ELECTRICAL ADJUSTMENTS
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
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.)
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
[RECORD/PLAYBACK HEAD AZIMUTH
ADJUST-MENT]
ADJUST-MENT]
DECK A DECK B
Note:
Perform this adjustments for both decks
Procedure:
1. Mode: Playback
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.
so that outputs match within 1dB of peak.
Tape
Signal
Used for
P-4-A100
10 kHz, –10 dB
Azimuth Adjustment
set
MAIN board
CN510
Pin 1 (L-CH)
Pin 3 (R-CH)
CN510
Pin 1 (L-CH)
Pin 3 (R-CH)
MAIN board
CN510
Pin 2 (GND)
CN510
Pin 2 (GND)
+
–
level meter
test tape
P-4-A100
(10 kHz, –10 dB)
P-4-A100
(10 kHz, –10 dB)
screw
position
position
L-CH
peak
peak
within
1dB
1dB
output
level
level
L-CH
peak
peak
R-CH
peak
peak
within
1dB
1dB
screw
position
position
R-CH
peak
peak
TUNER SECTION
0 dB = 1 µV
DECK SECTION
0 dB = 0.775 V
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