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PR-8210-A
11. Objective lens mounting
Р; M: stopper
Pan-head
screw 2x4
A
Objective lens
C
sey
Pan-head
screw 2x4 ^
Pallet
12. Check of stain on the optical parts
(1) Press the lever of the rotation jig and turn the
slider over.
(2) After
lighting
the laser, put an orange colored
paper under the objective lens, observe the pro-
jection of the beam on the paper.
(3) If the beam
is projected
unevenly, first blow
the dust on optical parts by an air blower, wipe
the
optical
parts off by a piece
of cleaning
paper wetted with the following abstergent.
Objective lens: Mixture of fron and ethanol
Grating:
Pure
fron
(Don't
wipe off grated
side)
Other
optical
parts:
Mixture
of fron
and
ethanol
CAUTION:
Do not clean transducer mirrors.
13. Photo detector positioning and 1/4 wave
plate adjustment
Preparation
(1) Mount the slider on the static jig (stand A) and
lock in place.
(2) Prepare amp. jig, laser power supply and a dual
trace oscilloscope, and connect them as shown
in the connection diagram.
NOTE
There
is no connecting post for housing N-4 in old static
jig.
Therefore,
it is necessary
to
modify
the connector
stand on the jig.
50
Adjustment
(1) Turn on the power of the amp. jig and light on
the laser.
(2) Adjust
the height
of the moveable
reflecting
mirror,
so
the reflected
beam
focuses
on
the
photo detector.
(3) Set the function
SW of the amp. jig to posi-
tion
3, for observing
the levels of TRKG
A
and TRKG B.
(4) Adjust
the photo
detector
position
to make
absolute value of TRKG
A and TRKG B equal
by turning the PD adjustment screws.
(5) Fine
adjust
the
height
of the
moveable
re-
flectiag mirror to make TRKG A and TRKG
B
levels maximum.
(6) Repeat the steps (4) and (5) once or twice.
(7) Set the function SW of the amp. jig into posi-
tion
2 for observing
the waveform
of focus
error.
(8j Tum
on the 300Hz
OSC
SW of the amp. jig
to drive the moveable reflecting mirror.
(9) Rotate the output
VR of the 300Hz OSC in
CW direction until a dip appears on the peak
points of the focus error waveform.
(10) Rotate
the 1/4 wave
plate to obtain maxi-
mum
focus error.
(11) Fine adjust the PD position to obtain maxi-
mum
focus error.
(12) Repeat
above
adjustment
steps
(3) to (11)
until maximum focus error is obtained.
(13) This adjustment
result
should
meet the fol-
lowing criteria.
* Focus error peak to peak value: more than
5.3V
* The difference between value A and value B:
within 10% of peak to peak value.
е ТЕКС
A and ТЕКС B should be approxi-
mately same level (absolute value).
(С
1/4 wave plate
uu 2 ы
|
PD adjustment =
——
т
|
(8%2%
B pins housing (N-4) 7
6 pins housing (N-5)
——B
\— Static jig
Moveabie reflecting mirror C»
H
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