Sony CDP-970 - Focus;Tracking Gain Adjustment

SECTION 2
ADJUSTMENTS
JSTMENTS
its
in the
order
given.
t No.
3-702-101-01)
disc
unless
1.
ipe
with
more
than
10MJ2 im-
.djustment/Lock Frequency
frequency
counter
I
t
TP(ASY),
uency
counter
to
the test points
(GND).
tch
on.
;o
that
the reading
on
the
fre-
4.3218MHz ±30kHz.
ency
adjustment)
iding wire from TP
(ASY).
IS-
18)
in and press
[>
button.
reading
on the frequency
counter
8 MHz.
5218MHz
±30kHz
tent
should
be made after replacing
Block.
oscilloscope
(DC range)
Focus Bias
Adjustment
This
adjustment should be
made
after replacing
the Optical Pick-up
Block.
Procedure:
main board
TP(RF)
O-
-p,.
I
TP (RFG)
O
U?- I
1.
Connect
oscilloscope
to
the test points
TP (RF)
and TP (RFG).
2. Turn
POWER
switch on.
3.
Put the disc(YEDS-lS)
in and press
>
button.
4.
Adjust
RV104
for an optimum
waveform
eye pat-
tern.
Optimum eye
pattern means that
shape
“O”
can be
clearly distinguished at
the center of the
waveform.
1.1-1.5VP-P
---0.1
-0.05V
A
1.
Connect
the
oscilloscope to
the test points
TP
(TEO)
and TP (GND).
2.
Ground TP
( ADJ
)
to
set an
adjustment mode.
3.
Ground TP(TES) and turn
POWER switch on.
4.
Put the
disc
(YEDS-1
8)
in and
press
i>
button.
5. Adjust
RVlOl so that positive and negative halves of
traverse waveform have the
same amplitudes.
6.
After
adjustment, cancel the
adjustment
mode.
TIME/DIV: 1ms
Wmm
mmm.m
oscilloscope
(DC range)
o
Focus/Tracking
Gain
Adjustment
A
frequency response
analyzer
is
necessary in
order
to
perform this
adjustment exactly.
However, this
gain
has
a
margine, so
even if it
is
slightly
off, there is
no problem.
Therefore, this ad-
justment is
not recomended generally to be per-
formed.
Focus/tracking
gains determine
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.
Gain
Symptoms
Focus
Tracking
• The time
until music starts
becomes
longer for STOP
->PLAY or
automatic
selection (W«
PMbuttons
pressed.
(Normally takes
about
2
seconds.)
low
low or
high
• Music
does not
start and
disc continues
to rotate
for STOP-*
>PLAY
or
automatic
selection
(
M4
*1
buttons pressed.)
low
•
Disc table
opens
shortly
after
STOP-*t>PLAY.
low
or
high
-
•
Sound is
interrupted
dur-
ing
PLAY. Or
time
count-
er
display stops
progress-
ing.
-
low
• 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, 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:
main
board
TP (FED Oe
7
TP
(FED)
"D
j
7-
TP
(TED
0»-
—
'
TP
(TEO)
O
^
1.
Keep the set
flat.
If the set is
not
horizontal, this adjustment
cannot be
performed due to
the gravity
against
the
2
axis
device.
2.
Insert the
disc
(YEDS-18)
and press
E>
PLAY
button.
3.
Connect the oscilloscope
to TP (FEl) and TP
(FED).
4.
Adjustment
RV103 so that
the
waveform is as
shown in the picture
below, (focus gain adjust-
ment)
VOLT/DI
V: 100
mV
TIME/DIV:
2 mS
lOOmV
OV
oscilloscope
(DC
range)
5.
Connect
the oscilloscope
to TP
(TEl), TP
(TEO).
6.
Adjust
RV102
so that
the
waveform
is
as shown
i
the
picture below, (tracking
gain adjustment)
•
Incorrect
Examples
(fundamental
wave
appears)
low
tracking gain
high tracking
gain
(higher frequency
of
the
fundamental
wave
than above)
. , .
_
, 1 1 j rr *
Adjustment Location:
main board
•
Incorrent Examples (DC level
is quite different
from the
adjusted waveform) (below)
(
high focus gain
VOLT/DiV:
100
mV
TP
(RFG)
-
4
-
-
5
-