CMT-M9, HCD-D11, HCD-T11 - Sony Audio Service Manual (repair manual). Page 12

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Note:
1. CD Block 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 the oscilloscope with more than 10M

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.

This adjustment is to be done when the optical block is replaced.

+
–

BD board

TP (RF)

TP (VC)

oscilloscope

(DC range)

1. Connect oscilloscope to test point TP (VC) and TP (RF) on BD

board.

2. Ground display board IC701 pin @¢ with the lead wire.
3. Turned power switch ON. (Stop mode)
4. Put disc (YEDS-18) in and press the 

^ button.

5. Press the 

^ button again. (Tracking servo ON)

6. Adjust RV101 so that the oscilloscope waveform is as shown in

the figure below (eye pattern).
A good eye pattern means that the diamond shape (≈) in the
center of the waveform can be clearly distinguished.

7. Remove the lead wire connected in step2.

•

 RF signal reference waveform (eye pattern)

VOLT/DIV: 200 mV
TIME/DIV: 500 ns

level:
1.3 

±

 0.3Vp-p

When observing the eye pattern, set the oscilloscope for AC
range and raise vertical sensitivity.

+
–

BD board

TP (FEO)

TP (VC)

oscilloscope

Procedure:
1. Connect oscilloscope to test point TP (VC) and TP (FEO) 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.)

5. Check the oscilloscope waveform (S-curve) is symmetrical be-

tween A and B. And confirm peak to peak level within 2.4 ± 0.7
Vp-p.

A

B

symmetry

within 2.4 

±

 0.7 Vp-p

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 bright-
ness to obtain best waveform.

S-curve waveform

+
–

BD board

TP (RF)

TP (VC)

oscilloscope

Procedure:
1. Connect oscilloscope to test point TP (VC) and TP (RF) on BD

board.

2. Turned Power switch on.
3. Put disc (YEDS-18) in and press the 

^ button.

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

clearly distinguished at the center of the waveform.

RF signal waveform

+
–

BD board

TP (TEO)

TP (VC)

oscilloscope

(DC range)

Procedure:
1. Ground display board IC701 pin @¢ with the lead wire.
2. Connect oscilloscope to test point TP (TEO) on BD board.
3. Turned Power switch on.
4. Put disc (YEDS-18) in and press the 

^ button.

5. Confirm that the oscilloscope waveform is symmetrical on the

top and bottom in relation to 0V, and check this level.

VOLT/DIV: 200 mV
TIME/DIV: 500 ns

level:
1.3 

±

 0.3Vp-p