Sony CDP-CX240 Service Manual page 20

Disc Sensor Adjustment
Perform this adjustment after completing all adjustments of the
mechanism section.
If not performed accurately, the presence of the disc may not be
detected properly.
Connection 1:
CN506 of MAIN board
T1 : Pin 1 (TS. 1)
T2 : Pin 2 (TS. 2)
D0 : Pin 4 (D. SENS)
Waveform 1:
A B
Connection 2:
CN506 of MAIN board
T1 : Pin 1 (TS. 1)
T2 : Pin 2 (TS. 2)
D1 : Pin 4 (D. SENS)
Waveform 2
Z
X Y
oscilloscope
1 k Ω
T1
T2
D0
oscilloscope
T1
T2
D1
Procedure:
1. Connect the oscilloscope to Pins 1, 2, and 4 of CN506 of the
MAIN board. Also connect a 1 kΩ resistor to Pin 4 at the same
time. (Connection 1)
2. Check that no discs are loaded in the unit.
3. With the power OFF, press the 1/u button while pressing the
INPUT button, and turn on the power at the same time.
4. The rotary table will continue rotating in the clockwise direction.
5. Observe the waveform at that time on the oscilloscope.
6. Loosen the screw securing the LUMINOUS board slightly.
7. Slide the LUMINOUS board to the left and right so that the
peak of the D0 waveform is at the center between the descending
point of the T1 waveform and ascending point of the T2
waveform. (Waveform 1) After adjusting, apply locking
compound.
8. Disconnect the resistor connected to Pin 4 of CN506 of the
MAIN board. (Connection 2)
9. Observe the waveform on the oscilloscope. (Waveform 2)
10. Adjust RV501 of the MAIN board so that the waveform on the
oscilloscope satisfies the following adjustment value 1.
11. Press the 1/u button and turn OFF the power.
12. Press the 1/u button, turn on the power, press the OPEN/
CLOSE button, and open the front cover. Next rotate the DISC/
CHARACTER dial in the counterclockwise direction
continuously so that the rotary table rotates continuously in the
counterclockwise direction.
13. Observe the waveform on the oscilloscope and confirm that it
satisfies the adjustment value 2 (waveform 3). If it does not,
adjust RV501 of the MAIN board.
Waveform 3:
Z
X Y
– 20 –
LUMINOUS board
T1
T2
D1