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4 Grating Adjustment-2
«
Grating Adjustment-2 may be performed ih Grating
Adjustment-1 (rough adjustment and fine adjust-
ment).
* Purpose:
The grating may need adjustment in a replaced
pick-up unit.
+ Maladjustment symptoms:
No disc playback, track jumping.
+ Measuring equipment / jigs:
Oscilloscope, grating adjustment driver, low-pass
filter
¢ Measuring point:
TEY
«Test disc and setting:
SONY TYPE 4 (or ABEX TCD-782)
Test mode
¢ Adjustment position:
Pick-up grating adjustment hole
MAIN
UNIT
Oscilloscope
REFOUT
Adjustment Procedure
. Inthe test mode, set a test disc-loaded magazine and
select the tray with a test disc.
. Switch regulator ON .
. Using the prior mea key, move the pick-up to cen-
ter of the test disc.
. Press the Fe2 key to close focus.
. Insert the adjusting screwdriver in the slit for the pick-
up grating adjustment and adjust the grating to seek
out the null point. For details, see following page.
. As the screwdriver is slowly turned clockwise from
the null point, the amplitude of the waveform in-
creases gradually. As the screwdriver continues to
be turned, the amplitude of the waveform decreas-
es again. Adjust the grating to a point at which the
amplitude of the waveform first reaches the maxi-
mum while the screwdriver is turned clockwise from
the null point.
16
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