Electrical Adjustments - Sony HCD-GX40 Service Manual

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3 7 63 1515 0
TUNER SECTION
AM IF Adjustment
AM RF Signal generator
30% amplitude
modulation by
400Hz signal
output level : as low as possible
set
Procedure:
1. Set the frequency of the AM RF signal generator to 1000 kHz
(at 10 kHz step) or 999 kHz (at 9 kHz step).
2. Tune the set to AM 1000 kHz (at 10 kHz step) or 999 kHz (at 9
TE
L 13942296513
kHz step).
3. Adjust IFT101 so that the reading on level meter becomes in
maximum.
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ELECTRICAL ADJUSTMENTS

set
AM ANTENNA terminal
(JK103)
level meter
16 Ω
headphones jack (JK691)
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SECTION 4
2 9
8
FM Tuned Level Adjustment
FM RF Signal generator
Carrier frequency : 98 MHz
Modulation : AUDIO 1 kHz, 75 kHz
: 30 dB (at 75 Ω open)
Output level
Procedure:
1. Supply a 98 MHz signal at 28 dB from the ANTENNA terminal.
2. Tune the set to 98 MHz.
3. Adjust RV101 to the point (moment) when the TUNED
indicator will change from going off to going on.
Adjustment Location: MAIN board
Null Adjustment
FM RF Signal generator
Carrier frequency : 98 MHz
Modulation : AUDIO 1 kHz, 75 kHz
: 60 dB (at 75 Ω open)
Q Q
Output level
3 6 7 1 3 1 5
Procedure:
1. Supply a 98 MHz signal at 60 dB from the ANTENNA terminal.
2. Tune the set to 98 MHz.
3. Measure voltage between pin 21 and pin 23 of IC 101. Adjust
T101 until the voltage becomes 0 V.
Adjustment Location: MAIN board
[MAIN BOARD] Component side
T101: NULL
IFT101: AM IF
RV101:
FM TUNED LEVEL
co
.
HCD-GX40
9 4 2 8
75 Ω coaxial
FM ANTENNA terminal
deviation (100%)
(JK103)
75 Ω coaxial
FM ANTENNA terminal
deviation (100%)
(JK103)
0 5 8 2 9 9 4 2 8
m
9 9
set
set
9 9
17