Sony HCD-DX50/RG80 Service Manual page 17

TUNER SECTION
FM Tuned Level Adjustment
FM RF SIGNAL GENERATOR
Carrier frequency : 98 MHz
Modulation : AUDIO 1 kHz, 75 kHz
deviation (100%)
: 28 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 RV11 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
deviation (100%)
: 60 dB (at 75 Ω open)
Output level
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 22 and pin 3 of IC11. Adjust
T11 until the voltage becomes 0 V.
Adjustment Location: MAIN board
Adjustment Location
[MAIN BOARD]
(Component Side)
NULL
FM TUNED LEVEL
T11
RV11
75 Ω coaxial
set
FM ANTENNA terminal
(TM1)
75 Ω coaxial
set
FM ANTENNA terminal
(TM1)
CN304
CN301
3 1
RV301
CN302
RV302
RV303
CN303
RV351
RV304
RV354
CD SECTION
Note :
1. CD Block is basically designed to operate without adjustment.
Therefore, check each item in order given.
2. Use LUV-P01 (4-999-032-01) unless otherwise indicated.
3. Use an oscilloscope with more than 10MΩ impedance.
4. Clean the object lens by an applicator with neutral detergent
when the signal level is low than specified value with the
following checks.
S-Curve Check
BD board
TP(FEO)
TP(DVC)
Procedure :
1. Connect an oscilloscope to TP (FEO).
2. Connect between TP (FEI) and TP (DVC) ( 1.65 V) by lead
wire.
3. Turn Power switch on.
4. Load a disc (LUV-P01) and actuate the focus search. (In
consequence of open and close the disc tray, actuate the focus
search)
5. Confirm that the oscilloscope waveform (S-curve) is
symmetrical between A and B. And confirm peak to peak level
within 2 ± 0.5 Vp-p.
S-curve waveform
6. After check, remove the lead wire connected in step 2.
Note : • Try to measure several times to make sure than the ratio
of A : B or B : A is more than 10 : 7.
• Take sweep time as long as possible and light up the
brightness to obtain best waveform.
RF Level Check
BD board
TP(RFDC)
TP(RFAC)
TP(DVC)
Procedure :
1. Connect an oscilloscope CH1 to TP (RFDC) and CH2 to TP
(RFAC).
2. Turn Power switch on.
3. Load a disc (LUV-P01) and playback.
4. Confirm that oscilloscope waveform is clear and check if RF
signal level is correct or not.
HCD-DX50/RG80
Oscilloscope
symmetry
A
within 2 ±0.5Vp-p
B
oscilloscope
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