Electrical Adjustments - Sony HCD-RG60 Service Manual

FM Tuned Level Adjustment
FM RF Signalgenerator
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 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 Signalgenerator
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 21 and pin 23 of IC 101. Adjust
T101 ubtil the voltage becomes 0 V.
Adjustment Location: MAIN board
Adjustment Location
[MAIN BOARD] Component side
T101:NULL
RV101:FM TUNED LEVEL
T101
RV101
T102
IFT101
SECTION 5

ELECTRICAL ADJUSTMENTS

75 Ω coaxial
set
FM ANTENNA terminal
(TM101)
75 Ω coaxial
set
FM ANTENNA terminal
(TM101)
RV661:TAPE SPEED
RV661
CD SECTION
Note :
1. CD Block is basically designed to operate without adjustment.
Therefore, check each item in order given.
2. Use YEDS-18 disc (3-702-101-01) 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(VC)
Procedure :
1. Connect oscilloscope to TP (FEO).
2. Connect between TP (FEI) and TP (VC) by lead wire.
3. Connect between TP (AGCCON) and TP (D GND) by lead wire.
4. Turn Power switch on.
5. Load a disc (YEDS-18) and actuate the focus search. (In
consequence of open and close the disc tray, actuate the focus
search)
6. Confirm that the oscilloscope waveform (S-curve) is
symmetrical between A and B. And confirm peak to peak level
within 4 ±1 Vp-p.
S-curve waveform
7. After check, remove the lead wire connected in step 2 and 3.
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(RF)
TP(VC)
Procedure :
1. Connect oscilloscope to TP (RF).
2. Connect between TP (AGCCON) and TP (D GND) by lead wire.
3. Turned Power switch on.
4. Load a disc (YEDS-18) and playback.
5. Confirm that oscilloscope waveform is clear and check RF signal
level is correct or not.
6. After check, remove the lead wire connected in step 2.
HCD-RG60
Oscilloscope
symmetry
A
within 4 ±1Vp-p
B
oscilloscope
17