Dual CS 731 Q - Tonearm Assembly and Adjustment; Tonearm Bearing Friction; Tonearm Removal from Bearing Frame

When
the
stroboscope
markings
seem
to
be
stationary
both
по-
minal
speeds
(33
1/3
and
45
rpm)
are
accurately
adjusted.
If
the
markings
seem
to
run
ahead
the
speed
is
higher.
If
the
markings
seem
to
run
back
the
speed
is
lower
than
the
nominal
speed.
By
means
of
the
speed
of
the
apparently
“wandering”
markings
the
speed
selected
with
potentiometer
(14)
can
be
determined
at
high
speeds:
1
graduation/sec.
=
0.9
96
deviation.
After
releasing
the
fixing
screw
(159)
and
removing
both
fillister
head
cap
screws
(96)
the
stroboscope
housing
can
be
removed
(149).
After
re-
moving
the
retainer
piece
(147)
the
three
LED's
(148)
can
be
re-
placed.
Tonearm
and
tonearm
suspension
The
light,
torsion-resistant
all-metal
tonearm
is
twingimbal
mounted.
Suspension
is
by
means
of
four
hardened
and
precision
polished
steel
points
which
rest
in
precision
ball
bearings.
The
tonearm
bearing
friction
is
thus
reduced
to
a
minimum.
Bearing
friction
vertical
0.07
mN
(0.007
g)
Bearing
friction
horizontal
0.15
mN
(0.0159)
as related to stylus point.
This
ensures
extremely
favorable
pick-up
conditions.
Before
setting
the
tracking
force
corresponding
to
the
built-in
pick-up
cartridge
the
tonearm
is
balanced
at
O
position
of
the
tracking
force
scale.
Coarse
adjustment
is
carried
out
by
moving
the
weight
with
stem
(60)
subsequent
fine
adjustment
by
turning
the front knurled
ring on the weight.
The
balance
weight
is
designed
so
that
pick-up
cartridges
having
a
dead
weight
(including
fitting
material)
of
2
—
9
g
can
be
balanced.
The
tracking
force
is
produced
by
tensioning
the
coil
spring
fitted
in
the
spring
housing
(74).
The
rotary
knob
(69)
is
provided
with
a
scale
which
permits
accurate
adjustment
of
the
tracking
force
in
the
range
from
0
—
20
mN
(0
-
2
p)
by
means
of the
marking
dots.
Fitting a 1/2" cartridge
The description of retrofitment for fitting а 1/2“ cartridge (ге-
placement of carrier plate etc.) should be taken from the opera-
ting instructions.
Fig.7
27
52
84
Fig.6
Й
147
146
149
96
Ветоуа! of tonearm from bearing frame
1) Secure unit in repair jig. Remove weight (60). Unscrew ten-
sioning screw (52). Set rotary knob (63) to 0.
Turn unit upside down.Remove hexagon nut (34) and screening
plate (119). Unsolder tonearm leads on muting switch (120).
Unscrew tensioning screw (70). Remove rotary knob (69),
disc (68) and indicator (67).
4) Loosen locking nut (61) and unscrew threaded pin (65).
5) Remove tonearm (30) with bearing (71).
Assembly takes place in reverse order.
2
3|
Removal of tonearm assembly with tonearm bearing
Proceed as follows:
1, Secure unit in repair jig. Set rotary knob (69) to 0. Lock
tonearm (30). Remove weight (60)
2. Turn unit upside down. Remove hexagon nut and screening
plate (119). Unsolder tonearm leads on muting switch (120).
3. Remove retainer disc (91). Remove main lever (167) and
bearing block (166). Remove securing disc (89). Lift off ad-
justing bar (168) and rotary bearing (170) and swivel to motor.
141
187
96
168
190
167 176
97