Electrical Checks - Sony CDP-XE270 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. Connect an oscilloscope to test point TP (FE1) and TP (VC)
on the BD board.
2. Turn the power on and insert the disc (PATD-012).
3. Turn the power off and enter the ADJ mode. (Refer to 4. Test
Mode)
4. Turn the power on to playback the second track and press the
button to stop playing back.
x
[REPEAT]
5. Press the button. (The object lens moves up and
down)
6. Confirm the oscilloscope waveform (S-curve) is symmetrical
between A and B. And check 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 (See page 12)
RFDC Level Check
Connection:
BD board
TP (RFDC)
TP (VC)
SECTION 5

ELECTRICAL CHECKS

impedance.
oscilloscope
+
–
symmetry
A
within 2 1 Vp-p
B
oscilloscope
+
–
Procedure:
1. Connect an oscilloscope to test point TP (RFDC) and TP (VC)
on the BD board.
2. Turn the power on and insert the disc (PATD-012).
3. Turn the power off and enter the ADJ mode. (Refer to 4. Test
Mode)
4. Turn the power on to playback the second track.
5. Confirm that oscilloscope waveform is clear and check RFDC
signal level 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 (See page 12)
RFAC Level Check
Connection:
BD board
TP (RFAC)
TP (VC)
Procedure:
1. Connect an oscilloscope to test point TP (RFAC) and TP (VC)
on the BD board.
2. Turn the power on.
3. Turn the power off and enter the ADJ mode. (Refer to 4. Test
Mode)
4. Turn the power on to playback the second track.
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 (See page 12)
CDP-XE270/XE370
Ver 1.1 2001.07
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level: 1.15 0.35 Vp-p
VC
oscilloscope
+
–
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level: 1.35 0.4 Vp-p
11