MECHANICAL MEASUREMENTS AND ADJUSTMENTS
Height
seHing of the turntable
For
th
i
s
alignment
the unit
should
be
in
the
position
of
normal
end
use.
The
servicing
supports
4822 395 30202
can
be
used
here.
Playback
track
1 of disc 4822 397 30096.
(Disc without
defects).
Connect
a
D.C.
voltmeter
between the negative of
the
focus
motor and earth of
the
preamplifier
print.
Adjust
the
height
of the
turntable
with
bearing
screw 51
in
such
a
way.
that
the
voltage
is 0 V +/- 100 mY.
Seal
hereafter
the
screw
with
sealing
paint.
Checking the
30 7(J? A�!J.
Place
mirror
4822 395 90205 on
the
objective
and
glass
disc 4822 39590204
(with
disc
hold-down
482253260906)
on the turntable.
Locate
the
unit
under
a
light
source
and under
this
light
source
a
straight
line
should
run
(e.g.
fluorescent tube
with
grid).
Set
the
arm
to
mid-position.
Turn
the unit
until
th
e
arm
is
parallel
to
the line
under
the
light source
(see Fig.).
Look
in the
direction
and
in
the
prolongation
of this line to
its reflection
on
glass disc
and
mirror.
.
These lines
should
not
be more
than
4 mm
a
pa
r
t
:
Position the set in
such
a
way
that
one line
runs
across
the
centre
of
the
mirror.
When
the
other
line
remains inside
the mirror's surface, the
distance
is
� 4
mm.
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Rotate
the
CD mechanism
through
900
relative
to the
previous
position.
The
arm
must
be
kept
in
mid-position (see Fi
g
.
)
.
Repeat
the previous
measurement.
Adjusting
the
angle
setting
With
respect
to
the
adjustment
of the
angle
between disc
and
light
path. the
f
a c
t
o
ry has
looked
for
a
compromise
between
minimum angle
deviation
and
minimum
arm
friction.
If
the measurements
show
that
the
angle
falls
outside
the
tolerance given.
the angle
should
NOT be adjusted
for
minimum
deviation. but
just
within
t
o
l
erance
.
The
new
setting
shou Id
lie
between the "old" setting and the
optimum
sett
in
g
.
After
adjustment.
the
friction
of the
arm
should
be
checked.
This
is
done by means of
a
spring-pressure
gauge
which is connected
to
the c
o
unte
r
weight. The
friction
of the
arm.
measured
over
the
total
scanning
deflection.
is
not
a
l
l
owed
to-exceed 30 mN.
When
the
friction
appears
to be too high. the angle
should
be reset
to
its
old
value.
Then
replace
the
arm by
a new
one
and
check the angle once
more.
Adjustment
of the
angle
is performed
as
follows:
Place the set
on
the
servicing
supports 482239530202.
Loosen
screws
C
(see Fig.)
until
bearing
plate D
can
be
sh
if
t
e
d
.
Correct
the
angle
setting
by shifting the
bearing
plate
in
the
direction indicated
on the F
i
gure
.
Tighten
screws
C
ensuring
that
the setting does not
drift.
Double
check
the
angle
setting
in
two
directions.
Attention
After setting the angle,
t
he height setting of the turntable
should be checked.
11
11
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30110 AIS
