Optical Assembly Tests; S Curve Check; E-F Balance Check - Sony CDP-CX235 Training Manual

Optical Assembly Tests

There are three basic checks for the optical assembly.

S Curve Check

In this procedure you will check the A-D detectors to see if they are bal-
anced with sufficient output level to produce RFO for play.
1. Load a YEDS-18 test disc into the CD changer so it is chucked.
2. Unplug the CD Changer from AC.
3. Connect the DC coupled scope to FE1 on the BD board.
4. Jump ADJ on the Main board to ground.
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5. Plug the CD Changer into AC to enter the test mode.
6. Press the Front panel CHECK button to activate and repeat focus
search. An S curve waveform should appear.
A
2
CH1 1.00 V=
C H 2 ! 2 . 0 0 V = M T B 2 . 0 0 m s - 3 . 1 0 d v c h 1 +
B
The S curve should be between 2 to 4Vp-p and must be symmetrical
above and below the base line (A=B).
7. Unplug the AC to escape from the ADJ test mode.

E-F Balance Check

In this procedure you will check the E & F tracking detectors. Defective
detectors will cause skipping.
8. Plug the CD Changer into AC and press the Power On button.
9. Touch your DC coupled scope to the Vc test point on the BD board
and mark this reference position on the scope with masking tape. Vc
will be about 2.5Vdc.
10. With the disc still chucked and the ADJ test point grounded, move the
scope probe to the TE test point on the BD board.
Press the to select track 5 and press PLAY.
11.
12. Press the front panel GROUP 3 button to disable the tracking servo.
The small 0.5Vp-p tracking error signal will change to a large 1.4Vp-p
traverse wave.
PKD