Sony CFD-50 - Page 11

REFERENCE
Focus/Tracking Gain Adjustment
A frequency response 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, it is more susceptible to
mechanical shock and skipping occurs more easily.
@ When gain adjustment is off, the symptoms below
appear.
low or high
@ The time until music starts
becomes longer for STOP
=P PLAY or automatic
selection (Hed PR buttons
pressed. (Normally takes
about 2 seconds.)
e Music does not start and
disc continues to rotate
for STOP => PLAY or
automatic selection (Hed
bi buttons pressed.)
e Sound is interrupted dur-
ing PLAY. Or time count-
er display stops progress-
ing.
e More poise during 2-axis
device operation.
The following is a simple adjustment method.
— Simple Adjustment —
Note: Since exact adjustment cannot be performed, remem-
ber the positions of the controls before performing the
adjustment. If the positions after the simple adjust-
ment are only a little different, return the controls to
the original position.
Procedure:
1. Keep the set horizontal.
If the set is not horizontal, this adjustment
cannot be performed due to the gravity against
the 2 axis device.
2. Insert disc (YEDS-18) and press ®» PLAY button.
3. Connect the oscilloscope between IC701 pins 62)
and 6) .
4. Adjustment RV705 so that the waveform is as
shown in the figure below. (focus gain adjustment)
@ Incorrent Examples (DC level changes more than
on adjusted waveform)
low focus gain
—-OV
VOLT/DIV:
TIME/DIV: 2mS
VOLT/DIV:
TIME/DIV: 2mS
— 250mvVv
700 mV
100 mV
VOLT/DIV: 100 mv
TIME/DIV: 2mS
5. Connect the oscilloscope between IC701 pins @)
and 26) :
6. Adjust RV704 so that the waveform is as shown in
the figure below. (tracking gain adjustment)
VOLT/DIV: 1V
TIME/DIV: 2ms
OV
@ Incorrect Examples (fundamental wave appears)
low tracking gain
VOLT/DIV: 1V
TIME/DIV: 2mS
— OV
high tracking gain
(higher fundamental wave than for low gain)
VOLT/DIV: 1V
TIME/DIV: 2mS
— Ov
Adjustment Location: CD main board (conductor side) Remove the solder bridge while -
adjusting the tracking gain.
(After adjustment make the
solder bridge.)
oscilloscope
(DC range)
Remove the solder bridge while
adjusting the focus gain.
—— (After adjustment make the
solder bridge.)
RV705
1C701 pin @
1C701 pin @
IC701 pin @
RV704