Dual 704 - Tonearm Suspension and Friction; Bearing Friction; Tracking Force Adjustment; Assembly Removal

Fig.
8 Tonearm-Tonearm Suspension
31
29 183 24
Tonearm-Tonearm
Suspension
69
48
26 68 51 59
61
36 52 38
The feather-light,
extremely torsion resi-
stent all-metal tonearm is suspended in a
gimbal.
Suspension is by means of 4 hardened
and precision polished steel points which
rest in precision
ball bearings. Tonearm
bearing friction is
thus reduced to a mini-
mum.
Bearing
Bearing
friction
friction
vertical
horizontal
▪ 0.007 p
▪
0.015 p
as related to
stylus point.
As a
result, it ensures most favourable
pick -up conditions. Before
adjusting the
pick -up force to suit
the built-in pick -up
cartridge the
tonearm is balanced with the
scale set to zero. Coarse
adjustment is car-
ried out by
moving the weight with
the stem
(49), the subsequent
fine adjustment by
tur-
ning the weight. The balance weight is de-
signed such
that pick -up cartridges
having
a
deadweight of 4.5 - 10 g can be
balanced.
lt takes the form of a
anti-resonator thus
absorbing the
vibration energy in the range
Fig. 9
36
56
57
38
201
128
207
211
37
42
205
49
of tonearm and chassis resonance. For this
purpose, the
inner part weight is matched
to the tonearm resonance and thus acts as
anti-resonator by
means of antiphase vibra-
tion. The
outer part of the balance weight
taking the form of a higher balanced
anti-
resonator prevents transmission of partially
occurring chassis resonance to the
tonearm.
The tracking force is adjusted
by turning
the
graduated spring housing (59)
incorpo-
rating a coil spring. The
scale has markings
for a range of
adjustment from 0 to 30 mN
(0 to 3 p) which
permit accurate adjustment
of the
tracking force. One graduation in the
range of 2 - 15 mN (0.2 - 1.5
p) corresponds
to 1 mN (0.1 p), in the range of
15 - 30 mN
(1.5 - 3 p) to 2.5 mN (0.25 p).
Removal of tonearm assembly with tonearm bearing
1. Secure
unit in repair
jig. Remove
weight
(49) undo
fixing screw
(52). Set
tracking
force scale
(59) to zero.
2. Move
unit into head
position.
Remove
screening
plate (150).
Unsolder
tonearm
on muting
switch (149).
3. Move unit
into normal
position. Turn both
mounting
screws - SW 4.5 -
(55) counter-
clockwise to
the stop of the
bearing fra-
me (51).
Attention: Observe
the bayonet mounting.
Slide tonearm
(48) rearwards and
remove
it upwards from
the bear-
ing
frame.
For installation proceed in the
reverse
order.
Removal of tonearm
from bearing frame
Proceed as follows:
1. Secure unit in
repair jig. Set graduated
spring housing (58) to zero.
Arrest tone -
arm (48). Remove
weight (49).
2. Loosen tension layer (63) and bring tone -
arm (48)
in its highest position using
knob (65). Fasten tension
layer (63).
Bring knurled ring (68) in position "3".
10