Read Sony HTC-V5550 / MHC-V5550 / MHC-V7770AV Service Manual online
— 14 —
CD SECTION
Notes:
1. CD block basically constructed to operate without adjustment. There-
fore, check each item in order given.
2. Use YEDS-18 disc (Part No.: 3-702-101-01) unless otherwise indicated.
3. Use the oscilloscope with more than 10 M
3. Use the oscilloscope with more than 10 M
Ω
impedance.
4. Clean an object lens by an applicator with neutral detergent when the
signal level is low than specified value with the following checks.
S-Curve Check
Connection:
Procedure:
1.
1.
Connect the oscilloscope to TP (FE) and TP (VC) on BD board.
2.
Connect between test point TP (FOK) and Ground by lead wire.
3.
Turned 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.)
actuate the focus search. (actuate the focus search when disc
table is moving in and out.)
5.
Confirm that the oscilloscope waveform (S-curve) is
symmetrical between A and B. And confirm peak to peak level
within 3.0 ± 1.0 Vp-p.
symmetrical between A and B. And confirm peak to peak level
within 3.0 ± 1.0 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 that 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
Connection:
Procedure:
1.
1.
Connect the oscilloscope to TP (RF) and TP (VC) on BD board.
2.
Turned power switch on.
3.
Put disc (YEDS-18) in and press the fl button.
4.
Confirm that the oscilloscope waveform is clear and check RF
signal level is correct or not.
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.
within 3.0 ± 1.0 Vp-p
RF signal waveform
When observing the eye pattern, set the oscilloscope for AC range
and raise vertical sensitivity.
and raise vertical sensitivity.
When a general remote commander is not used (1 Track Jump
Check):
Procedure:
1.
Check):
Procedure:
1.
Connect the oscilloscope to TP (TE) and TP (VC) on BD board.
2.
Turned power switch on.
3.
Put disc (YEDS-18) in and press the fl button, and play the
number five track.
number five track.
4.
Press the fl button. (Becomes the 1 track jump mode)
5.
Confirm that the level B of the oscilloscope's waveform and
the A (DC voltage) of the center of the traverse waveform.
Confirm the following:
the A (DC voltage) of the center of the traverse waveform.
Confirm the following:
1 track jump waveform
Connection Location:
[BD Board] (Side A)
A – B
2 (A + B)
×
100 = ± 7 (%)
level: 1.3 ± 0.6 Vp-p
+
–
–
BD board
TP (FE)
TP (VC)
oscilloscope
A
B
symmetry
+
–
–
BD board
TP (RF)
TP (VC)
oscilloscope
(AC range)
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
(with the 10: 1 probe
in use)
TIME/DIV: 500 ns
(with the 10: 1 probe
in use)
level: 1.3 Vp-p
+0.25
–0.20
Center of the waveform
B
symmetry
A (DC voltage)
0V
CN102
CN101
IC103
IC101
TP
(FOK)
TP
(TE)
TP
(FE)
TP (RF)
TP (VC)
TP (VC)
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