Sony HCD-GRX5, Service Manual

Page: 16 / 70

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Note:
1. CD Block is basically designed to operate without adjustment. There-
fore, 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 10 M
Ω
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
Procedure:
1. Connect oscilloscope to test point TP (FEO).
2. Connect between test point TP (FOK) and GND by lead wire.
3. Turn Power switch on.
4. Put disc (YEDS-18) in and turned Power switch on again and
actuate the focus search. (Actuate the focus search when disc
table is moving in and out.)
5. Check the oscilloscope waveform (S-curve) is symmetrical
between A and B. And confirm peak to peak level within 3±1
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
Procedure:
1. Connect oscilloscope to test point TP (RF) on BD board.
2. Turned Power switch on.
3. Put disc (YEDS-18) in and playback.
4. Confirm that oscilloscope waveform is clear and check RF
signal level is correct or not.
Note: Clear RF signal waveform means that the shape “ ≈ ” can be clearly
distinguished at the center of the waveform.
• FR signal
+
–
BD board
TP (FEO)
TP (VC)
oscilloscope
A
B
symmetry
within 3
±
1 Vp-p
+
–
BD board
TP (RF)
TP (VC)
oscilloscope
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level:
1.3
±
0.3 Vp-p
E-F Balance (Traverse) check
(Without remote commander)
Procedure:
1. Connect oscilloscope to test point TP (TEO) on BD board.
2. Turned Power switch on. Press
[FUNCTION]
button to select
CD.
3. Put disc (YEDS-18) in to play the number five track.
4. Press the
p button,
[ENTER/NEXT]
button and
^
but-
ton simultaneously several times to fluorescent indicator tube
display “SHUFFLE” is blink. (The sledding servo is turned
OFF.)
5. Check the level B of the oscilloscope’s waveform and the A
(DC voltage) of the center of the Traverse waveform.
Confirm the following:
Traverse waveform
6. Press the p button,
[ENTER/NEXT]
button and
^
button
simultaneously several times to fluorescent indicator tube dis-
play “SHUFFLE” is OFF. (The sleding servo is turned ON.)
Confirm the C (DC voltage) is almost equal to the A (DC volt-
age) is step 5.
Traverse waveform
+
–
BD board
TP (TEO)
TP (VC)
oscilloscope
A (DC
voltage)
B
0 V
level: 500
±
100 mVp-p
symmetry
Center of the waveform
C (DC
voltage)
0 V
Sled servo ON Sled servo OFF
CD SECTION
A
×
100 = less than ±7 (%)
B