Cd Section - Sony HCD-GRX30 Service Manual

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(FE)
TP(VC)
Procedure :
1. Connect oscilloscope to TP (FE).
2. Connect between TP (FEI) and TP (VC) by lead wire.
3. Connect between TP (AGCCON) and TP (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 (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.
Oscilloscope
symmetry
A
within 4 ± 1Vp-p
B
oscilloscope
— 16 —
Note : Clear RF signal waveform means that the shape " ◊ " can be clearly
distinguished at the center of the waveform.
RF signal waveform
VOLT/DIV : 200mV
TIME/DIV : 500ns
E-F Balance (1 Track jump) Check
oscilloscope
BD board
TP(TE)
TP(VC)
Procedure :
1. Connect oscilloscope to TP (TE) and TP (VC).
2. Turned Power switch on.
3. Load a disc (YEDS-18) and playback the number five track.
4. Press the ( button. (Becomes the 1 track jump mode.)
5. Confirm that the level B and A (DC voltage) on the oscilloscope
waveform.
1 track jump waveform
0V
level=1.3 ± 0.6Vp-p
A
Specified level: –– × 100=less than ±22%
B
6. After check, remove the lead wire connected in step 1.
RF PLL Free-run Frequency Check
Procedure :
1. Connect frequency counter to test point (PLCK) with lead wire.
frequency counter
BD board
TP (PLCK)
2. Turned Power switch on.
3. Put the disc (YEDS-18) in to play the number five track.
Confirm that reading on frequency counter is 4.3218MHz.
level : 1.45 ± 0.3Vp-p
center of
waveform
B
A (DC voltage)
symmetry