Sony CFD-21 - Page 13

CFD-20/30
5-4. 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.
© The time until music starts
becomes longer for STOP
=> P PLAY or automatic
selection ( Kd , DDI
buttons pressed). (Normally
takes about 2 seconds.)
low or high
@ Music does not start and
disc continues to rotate for
STOP =» P PLAY or —_—
automatic selection ( K€ ,
PPI buttons pressed).
@ Sound is interrupted during
PLAY. Or time counter
display stops progressing.
@ More poise during 2-axis
device operation.
high high
The following is a simple adjustment method.
— Simple Adjustment —
Note: Since exact adjustment cannot be performed, remember the
positions of the controls before performing the adjustment. If
the positions after the simple adjustment are only a little
different, return the controls to the original position.
Procedure:
oscilloscope
(DC range)
CD
MAIN
board
e
c—a—
FE (1C701 @) o<——__—_—_0+
TE (IC701 @) ot ----~-~- : -
ve (1C701 @)
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 @ and ©).
4.
Adjsutment
RV
702
so
that
the
waveform
is
as
shown
in
the
figure
below. (focus gain adjustment)
Adjustment Location:CD MAIN board (See page 15)
e Correct Example
VOLT/DIV: 100 m
TIME/DIV: 2mS
e@ Incorrent Examples (DC level changes more than on adjusted
waveform)
low focus gain
VOLT/DIV: 100 mV
TIME/DIV: 2 mS
— 250mV
—oV
high focus gain
VOLT/DIV: 100 mV
TIME/DIV: 2 mS