Sony HCD-D890AV Service Manual page 17

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CD SECTION
Note:
1. CD Block is basically constructed 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 test point TP (FEO).
2. Connect between test point TP (FOK) and Ground 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 be-
tween A and B. And confirm peak to peak level within 3 ± 1Vp-p.
S-curve waveform
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L 13942296513
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 bright-
ness to obtain best waveform.
RF Level Check
BD board
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 sig-
nal level is correct or not.
Note: Clear RF signal waveform means that the shape "◊" can be
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clearly distinguished at the center of the waveform.
RF signal waveform
.
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oscilloscope
symmetry
A
Within 3 ± 1 Vp-p
B
oscilloscope
TP (RF)
TP (VC)
x ao
y
VOLT/DIV : 200mV
i
TIME/DIV : 500ns
level : 1.3 ± 0.3 Vp-p
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8
E-F Balance (1 Track Jump) check
Procedure:
1. Connect oscilloscope to test point TP (TEO) on BD board.
2. Turned Power switch on.
3. Put disc (YEDS-18) in to play the number five track.
4. Press the "P (Pause)" button.
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:
• A/B x 100 = less then ± 7 (%)
• B = 500 ± 100 mVp-p
1 track jump waveform
0V
Q Q
3 6 7 1 3
Adjustment Location:
[BD BOARD] (Conductor Side)
TP
(TEO)
TP
(FEO)
TP
(GND)
IC103
IC102
u163
.
– 17 –
2 9 9 4 2 8
oscilloscope
BD board
TP (TEO)
TP (VC)
Symmetry
level : 500 mV ± 100 mVp-p
1 5 0 5 8 2 9 9 4
TP (RF)
TP
(VC)
TP
(FOK)
IC101
IC102
m
co
9 9
Center of the waveform
B
A (DC voitage)
2 8 9 9