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ADJUSTMENTS
1. Setting the service mode
(1)
(2)
(3)
(4)
Disconnect
the
AC
power
plug
from
the unit.
Press the PLAY/PAUSE
key or the MEMORY
key
due to discharge
C904
connected
to pin 18 of
1C
501
(RESET)
and
the
+V_
IN
smoothing
capacitor (C951). Consequently, pin 18 of IC 501
becomes "LOW".
Ground the pattern of TP36 (see wiring diagram of
page 38 ~ 39) using jumper wire.
Two kind of IC is used as !C501 in this unit.
Follow step according to the particular part No,
concerned.
TMP47C420AF8172Z
...Connect
the AC
power
plug. (This mean
is not
operation
of the power
switch ON/OFF)
TMP47C420AF8173Z
°° .Connect
the
AC
power
plug
while
pressing
the
PLAY key.
The player will be in the service mode and the LCD
displays « Og
og 00"
2. Particular operation in service mode
(1)
(2)
(3)
(4)
When the SKIP/SEARCH
key is pressed, the pickup
moves to the outermost or innermost portion of the
disc. This enables to check the operation of the sled
motor.
When
the MEMORY
key is pressed, the pickup
perform
a focus search. If a disc is loaded in the
unit, the focus servo will go "ON". If a disc is not
loaded, the focus search will take place indefinitely.
When the REPEAT
key is pressed in the condition
of step 2, the tracking servo will go "ON", and the
unit will go into a play condition.
When
the STOP
key is pressed at any
operating
mode, you can cancel the ongoing operation.
3. Cancelling service mode
Disconnect
the AC
power
plug. and then remove
the
jumper wire from the pattern of TP36. (See the wiring
diagram of page 38 ~ 39.)
Tracking balance adjustment
Test disc ;
YEDS
18 (Sony)
Measuring equipment
;
Oscilloscope
Connection point
; TP-3
Adjustment point
'
Adjustment value
;
a
b
SVR - 101
Waveform symmetry
Put the unit in the service mode.
Load the test disc and then press the MEMORY
key. The disc will rotate and the focus servo will go
ON,
Note: !f the pickup is at the innermost track, first
press the PP key to move the pickup slightly
to the outside and not to play the TOC (zero
pattern) on the disc.
Observe the tracking error signal ( from TP3 ) on
the oscilloscope
and adjust SVR101
so that the
waveform
becomes
symmetrical
with
respect
to
0 V. (See Fig. 1.)
Focus offset adjustment
Test disc ;
YEDS 18 (Sony)
Measuring equipment ; Oscilloscope
Connection point
; TP-2 (FE-Signal) TP - 1 (RF-Signal)
Adjustment value
:
o
when unit in STOP status
Connect the oscilloscope to TP2 (FE signal).
Connect the oscilloscope to TP1 (RF signal).
Follow steps (a) and (b) of the "Tracking balance
adjustment" to turn the focus servo "ON",
Press the REPEAT
key, The tracking servo will go
ON, and the player will be in a play condition.
Measure
the DC
offset voltage
of the waveform
[focus error signal from TP2] using a DC voltmeter,
and note the measured value.
Press the STOP key and remove the disc.
Adjust SVR102
so that the DC offset voltage at
TP2 becomes
the same
as the voltage measured in
step (e).
Re-load the disc, and then follow the steps (c) and
(d) to put the unit in a play condition.
OPENING EXPANDED
Ao—
Fig. 2
(
Voltage when unit in PLAY = Voltage
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