Sony cfd 515 service manual

Page 2

Focus Bias Adjustment
This adjustment is to be done when the optical pick-up block is
replaced,

Procedure:
Oscilloscope
(DC range)
CD MAIN boa/d
_._ IE

WmH%-fl+
WNQm-m

L__-

Put the set into test mode.

2. Connect oscilloscope between TP (RF) and 1'? (VC).

3. Press PM and H4 buttons to move the optical pick-up to the
center. (Move the optical piek to enable easy visibility of the eye pattern.)

4. Insert disc (YEDS-lS) in and press HI button,

5. Press the HI button. (Tracking Servo ON)

6. Adjust RV701 so that the oscilloscope waveform is as shown in
the figure below. (eye pattern)

A good eye pattem means that the diamond shape (0) in the
center of the waveform can be clearly distinguished.

7 i Release test mode after adjustment is completed

(

- RF signal reference waveform (eye pattern)

ii

VOLT/DIV .' 0.2 V
TIME/DIV .' 500 n5

9 9 O 9 9 9 9 O
\\\\'i"iiiti);t
\ttififiiiWW

MM) t

.a;.... A

When observing the eye pattern, 59! the oscilloscope for AC
range and raise venical sensitivity.

Adjustment Location: CD MAIN board (See page 24.)

Focus/Tracking Galn Adjustment

A frequency responce analyzer is necessary in order to perform this

adjustment exactly,

However. this gain has a margin, so even if it is slightly off. there is

no problem. Therefore, do not perform this adjustment,

Focus/tracking gain determines the pick-up follow-up (vertical and

horizontal) relative to mechanical noise and mechanical shock when

the 2-axis device operate

However, as these reciprocate, the adjustment is at the point where

both are satisfied

' When gain is raised, the noise when the 2-axis device operates
increases.

~ When gain is lowered, mechanical shock and skipping occurs more
easily.

- When gain adjustment is off. the symptoms below appear.

Galn

Focus Tracking

Symptoms

- The time until music starts becomes
longer for I-tHl on automatic
selection. low
(I44 , DH buttons pressed.)
(Normally takes about 2 seconds)

low or high

- Music does not start and disc
continues to rotate for I-tHI or
automatic selection,

04 , FM buttons pressed.)

- Sound is interrupted during PLAY,
Or time counter display stops - low
progressing.

- low

t More noise during 2-axis device

operation, high h'gh

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