Sony CDP-307ESD - Page 15

CDP-307ESD/950
Focus Bias Adjustment
This adjustment should
be
made
when
replacing Optical
Pick-up
Block.
oscilloscope
(DC
range)
Procedure
main board
TP(RF)
'
TP(RFG)
(
1.
Connect
oscilloscope to test points
TP(RF) and TP
(RF G).
2.
Turn POWER
switch on.
3.
Put disc
(YEDS
—
18)
in and playback
the 6th selection.
4.
Adjust
RV104
for
an
optimum waveform eye pattern
or
so
that the
peak
is
maximum. Optimum eye
pattern
means that shape
“O”
can be clearly distinguished
at
the center of the
waveform.
#
RF Signal
Reference
Waveform (eye pattern)
VOLT/DIV : 200mV
TIME/DIV : 500nS
When
observing the eye
pattern, set the
oscilloscope for
AC range
and
raise vertical sensitivity.
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.
6
When
gain
adjustment is
off, the
symptoms
below
appear.
"
'
—
~
—
—
Gain
Symptoms
~~~~
—
—
—
Focus
Tracking
The time
until
music starts
becomes
longer for
STOP
-*>PLAY or
automatic
selection
(W<
W
buttons pressed.
(Normally
takes
about
2
seconds.)
low
low
or
high
Music does
not
start and disc
continues
to
rotate for STOP
-*> PLAY
or auto
-
matic
selection
(W
buttons
pressed.)
-
low
Disc table
opens shortly
after STOP-*
>
PLAY.
low or high
-
Adjustment
Location
;
main boad