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DR - UA124X- 2, DR- UA124X- 3
DR - UA124X- 5
2. Tracking Error Balance Verification
•Objective
To verify
that
there is no variation in the sensitivity of the tracking photo diode.
•Symptom when out of
Play
does not start
or
track search is
impossible.
adjustment
•Measurement instru-
Connect the
oscilloscope
to
ment
connections
TRK. ERR.
(This connection
may be
via
a low pass filter.)
•Player state
Test mode, focus and spindle servos
closed and tracking servo open
[Procedure]
[Settings]
50
mV/division
5
ms/division
DC mode
•Adjustment location
None
•Disc
YEDS-7
I.
Move the
pickup
to midway across the disc (R=35
mm)
with
the SCAN FWD[>[> or REV
<l<l
key.
2. Press the (
l) +(TIME) key,
the (2) +(TIME)
key, then the
(3)
+(TIME) key in that order to close the focus servo
then the
spindle servo.
•
3.
Line up the bright line (ground)
at
the
center
of the
oscilloscope
screen
and
put the oscilloscope into DC mode.
4.
Supposing that
the
positive amplitude
of the
tracking error
signal
at
TRK ERR is (A) and the negative amplitude is
(B), the following expression is satisfied.
TI
A*B
T
A=B
When
A
~
8,
A- 9
x-1so5
GND
1
c
2 -
.
c
1
GND
When
A<8, 9 -A
x-1
s
os
li
1f\
J
~
c
2
-
.
l
When there is a DC
When there is no DC
component
component
3. RF Level Adjustment
•Objective
To
optimize the playback RF signal amplitude
• Symptom when out of
No play or
no
search
adjustment
•Measurement
instru-
Connect
the oscilloscope to RF.
• Player state
Test
mode,
play
ment connections
[Settings]
50 mV/division
•Adjustment location
VR20
I
(Laser
Power)
10 ms/division
AC mode
•Disc
YEDS-
7
[Procedure]
I.
Move the pickup to midway
across the
disc (R=35
mm)
with
the SCAN
FWD[>[> or
REV
<l<l
key, then
press
the (1)
+ (TIME)
key, the
(2)
+(TIME) key, the (3)
+(TIME)
key,
then the
(4)
+(TIME) key in
that
order
to close the
respective
servos
and put the player into
play
mode.
-
2.
Adjust VR201 (Laser Power)
so
that the RF signal amplitude is 1.8 Vp-p
±
O.
l
V.
26
(
(
(
(
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