Mechanical
Part
General
The
following itern numbers refer to the
spare
part
lists and
exploded
d ra win
gs.
The
cover
can simply be removed by
the
hinged
clips.
Base
The base
57
is secured by four
cheesehead self-tapping
screws
{base
set
55) and with
two screws 2O
on
the
spring
cluster.
Front
screen
The front screen
63
is secured
to the casing 95 by two hexagonal nuts
120.
Removing the
chassis complete
It is recommended
to
fol
low
the followin
g
instruct
ions
when dismantling
the chassis complete:
1
)
Remove cover
95 and turntable 92. Remove the
base
57.
2) Loosen the
three cheesehead
screws 93. Lift cover
94
and
turn so
that it can be removed
over
the
tonearm
bearing and
tonearm.
3) Swing in tonearm
135 and solder
connecting
leads. Hold chassis.
4) Remove
the
four
cheesehead
screws 19
of the spring cluster
17
and
remove
chassis from
the
casing
95-
Motor and
drive
Special tools and
measuring
equipment
are
necessary
when repairing
Dual EDS
501. Therefore
repairs to
motor and motor circuitry should
be carried
out
by an authorized Dual service agency.
Changing the
motor
circuitry
1
)
Disconnect the
connections to the
motor circuitry 44.
2)
Remove
the two cheesehead
screws
97.
3) Change the
motor circuitry 44.
Changing the motor mechanism
1) Unscrew the
two setscrews
51
and removethecone50and
washer52.
2) Disconnect the motor and
generator
power
connection from the
motor circuitry 44.
3)
Remove the
three
cheesehead screws 49. Replace the
motor me-
chanism
53.
Adlusting
the rated speed
(33,
45
rpm)
Adjustment should be
carried
out in the
following
order:
1) Set
the crystal/pitch
switch in
the crystal
position.
2) Set speed controlswitchover in
posltion
33.
3) Connect
point
1 4a
of
the motor circuitry to
earth.
4)
Adjust the rated speed 33 rpm
with
the aid of
the
built'in
strobos-
cope on control
R
9028
5) Set the speed control switch to
position
45.
6) Adjust
the
rated speed
45 rpm with the
built-in
stroboscope
on
control R
9024.
Pitch control
variation
Each rated speed can
be
varied
within
a
range of
+
5.5
a/o
with the
"pitch"
control.
When
the crystal/pitch switch is
in the crystal
position
the
turntable
speed
corresponds
exactly
to
the
adjusted rated speed. This
is carried
out lndependently of the
position
of
the
control.
Tonearm
and
tonearm bearings
Dismanting tonearm
complete
with
tonearm
bearings
It
is recommended
to follow the
following order:
1) Set the
control
knob
129
in
the
zero
position.
Lock the tonearm
135.
Loosen the tensioning screw
132 and
remove
the
weight 166.
2) Remove the
cheesehead screw
84,
the
hex nut
83 and
cover
plate
82.
Unsolder
the tonearm
leads
at the shortout
77.
3) Remove
the machine screw 181
,
the micro switch and
the switch
support 176.
4) Bemove
lock washer 155. Lift off
main
lever 154
and
bearing
sup
port
153.
5) Femovethehex
nut
110 andthe
sunk
screw 113
andcounter bearing
112.
6)
Hold
tonearm. Flemove
the
machine
screw 73 and
lift Tonearm cpl
.
Reverse thi
s
proced
ure when reassebli ng.
Please
bea
r in
mind
the
threshold
pins
is correctly
positioned
in the ball bearings.
Removing
the
tonearm
from
the bearing case
1) Remove weight 166.
Screw
out
tensioning screw 132
and set the
control
knob 129 in the
zero
position.
2) Remove
cheesehead screw
84 and
cover
plate
82.
Unsolder the tone-
arm
leads
at the
shortout 77.
3) Loosen
the countersunk screw
130. Femove control
knob 129
washer
128
and
pointer
127.
4)
Loosen
lock
nut
98 and remove setscrew
gg.
5) Remove
tonearm 135.
Assembly should
be
carried
out
in
the reverse
order.
Changing
the spring casing
Remove the tonearm
135
f
rom its bearings 1
26
fol
I owing the i
nstructions
described above. Remove
the spring case 133.
Special
attention must be
paid
to ensure that the coil spring fits in the
recess of the
bearing
134.
Reassemble the lonearm, Adjust the bearing
play
as described
below.
Adjustment of tonearm bearings
The tonearm must be
exactly
balanced. Both bearings should
have
very
little
or
no
play.
The
horizontal tonearm bearing
is
correctly ad.justed
when thetonearm canfreely
slide in
and
outwith the antlskat;ng adjust
ment set to
"0.5"
The vertical tonearm bearing
is
correctly adjusted
when the tonearm
freely
swings back into
position
after
being
tapped.
The
play
in the
horizontal
tonearm bearing can be adiusted with the
setscrew 99 and the counter
nut
98.
The
play
in
the
vertlcal
tonearm
bearing can
beadjusted with the selscrew 118 and thecounter
nut
119.
Shortout
Adiustment
point
When
the curve wheel is in the zero
position
the
contact distance
between the contact spring F and
shortout contact L should be 0.5 mm.
lf
necessary,
bend
shortout contact slightly and clean the contact spring
with a suitable cleaning agent.
Tonearm lift
Adjustment
point
The tonearm lift height
can be adjusted
by
means
of
the adjustment
screw
and should
be between ca.
5 mm.
Changing the lift board
'l
)
Lock tonearm 135 in
position.
Remove
the screw 181, the
micro
switch
34
and the swltch support 176. Remove
the lock washer
155.
Lift
off main
ever
1Sizl
with bearing
support'153.
2) Remove the lock washer
180 and the cam
wheel
179.
Loosen
the
machine
screw 108. Femove the
slide
bush
171, iift the
adjusting
bar
17O and remove the lift board 105.
Assembly
is
carried out
in
the reverse
oTder.
Adjustment
points
Set down
point
The
set down
point
of
the tonearm can
be altered with
the ecentric
boJt
E
(Adjusting
plate
71). The setting
is effective
not
only for 17 cm
but
also
for
30 cm records.
Shut-off
point
The
shut-off
point
can be
varied within
the shut-off range
(record
dia.
116 to 122
mm) .
Remove
platter
92.
Using
a screwdriver adjust
shut-off rail
15O through
the hole
in
cam
wheel
30.
Fuses
After removinq
the turntable 92
the
cover of the fuse
switch 27
can be
removed allowing
access to the fuse 28.
--\
12
_\_
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