Electrical Adjustments - Sony CDP-CE275 Service Manual

Note:
1. CD Block is basically designed to operate without adjustment. There-
fore, check each item in order given.
2. Use PATD-012 disc (4-225-203-01) unless otherwise indicated.
3. Use an oscilloscope with more than 10M
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
Connection:
BD board
TP (FE1)
TP (VC)
Procedure:
1. Set the test disc (PATD-012). Disc chucking operation is
complete, then press the
off.
2. Connect an oscilloscope to test point TP (FE1) and TP (VC)
on the BD board.
3. Connect between test point TP (ADJ) on the MAIN board and
GND by lead wire.
[POWER]
4. Press the button to turn the power on and enter the
ADJ mode.
Then playback the number two track automatically, press the
button to stop the playback.
x
[CHECK]
5. Press the button actuate the focus search. (actuate
the focus search when disc table is moving in and out)
6. Check the oscilloscope waveform (S-curve) is symmetrical
between A and B. And confirm peak to peak level within 2 ± 1
Vp-p.
S-curve waveform
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.
Checking Location: BD board
RFDC Level Check
Connection:
BD board
TP (RFDC)
TP (VC)
SECTION 5

ELECTRICAL ADJUSTMENTS

impedance.
oscilloscope
+
–
[POWER]
button to turn the power
symmetry
A
within 2 1 Vp-p
B
oscilloscope
+
–
Procedure:
1. Set the test disc (PATD-012). Disc chucking operation is
complete, then press the
off.
2. Connect an oscilloscope to test point TP (RFDC) and TP (VC)
on the BD board.
3. Connect between test point TP (ADJ) on the MAIN board and
GND by lead wire.
[POWER]
4. Press the button to turn the power on and enter the
ADJ mode, then playback the number two track automatically.
5. Confirm that oscilloscope waveform is clear and check the level
of between RFDC top and VC is correct or not.
Note: A clear RFDC signal waveform means that the shape " " can be
clearly distinguished at the center of the waveform.
RFDC signal waveform
Checking Location: BD board
RFAC Level Check
Connection:
BD board
TP (RFAC)
TP (VC)
Procedure:
1. Set the test disc (PATD-012). Disc chucking operation is
complete, then press the
off.
2. Connect an oscilloscope to test point TP (RFAC) and TP (VC)
on the BD board.
3. Connect between test point TP (ADJ) on the MAIN board and
GND by lead wire.
[POWER]
4. Press the button to turn the power on and enter the
ADJ mode, then playback the number two track automatically.
5. Confirm that oscilloscope waveform is clear and check RFAC
signal level is correct or not.
Note: A clear RFAC signal waveform means that the shape " " can be
clearly distinguished at the center of the waveform.
RFAC signal waveform
Checking Location: BD board
CDP-CE275/CE375
Ver 1.1 2001.07
[POWER]
button to turn the power
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level: 1.15 0.35 Vp-p
VC
oscilloscope
+
–
[POWER]
button to turn the power
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level: 1.35 0.4 Vp-p
13