Dual 721 - Tonearm Adjustments; Tonearm Bearing Adjustment; Vertical Tonearm Control; Anti-Skating Device

4
•
•
5. Unscrew machine
screw (232) and holding
spring (231).
6. Hold tonearm (50) and unscrew pin (214).
Unlock tonearm (50) and remove it care—
fully.
When
installing the tonearm complete with
suspension, proceed in reverse order con—
sidering the following points:
Place pressure spring (39) on axle of frame
(38). Both axles of bearing (56) should
align segment (230) accurately. Frame (38)
should not contact cover (73) after tighten—
ing bolt (214). Mount holding spring so that
it does not contact the setting plate when
moving the tonearm (50).
Replacing spring
hmnirm (58)
Remove tonearm (50) from bearing frame (53)
as described above. Loosen lock nut (48) and
threaded pin (49). Unscrew bearing screw
(60). Lift bearing
frame (53). Remove spring
housing (58)
and washer (59). When
install—
ing note that the
helical spring catches the
bearing frame. Slide in
washer (59) and
tighten
bearing screw (60).
Reinstall tone —
arm
(50). Set bearing play
as
described be—
lau using threaded pin (49) and lock nut
(48).
Adjusting the
Tonearm Bearing
First balance
tonearm exactly. Both
bearings
must have
slight, just
perceptible play.
The
horizontal
tonearm bearing is
correctly ad—
justed
when at
anti—skating settings
"0.5"
and
being touched it slides
in without re—
sistance. The vertical
tonearm bearing is
correctly adjusted
when it swings in
after
being
touches. The play
of the horizontal
tonearm bearing
should be adjusted with
threaded pin
(37), the play of the
vertical
tonearm bearing with
threaded pin (49).
Vertical Tonearm
Control
After loosening the
tension
lauer
(62) the
tonearm can
be shifted vertically within the
range
of approximately 8 mm by turning knob
(64). When turning knob (64) the pivot cam
(223) is moved thus shifting the cue con—
trol
assembly (210) and the tonearm bearing
(38) vertically. This device is used to main—
tain the vertical tracking angle of the pick —
up cartridge independent from its height
(distance between the mounting level of the
cartridge and stylus tip). The vertical
tracking angle is
properly adjusted — with
the stylus tip on the record — when the tone —
arm is exactly paralleled to it. To check
for
correct adjustment proceed as
follows:
Disconnect unit plug from
power line. Cor—
rectly
balance tonearm and adjust
tracking
force. Put
a 30 cm record on the platter.
Now, lauer the
stylus on the run—out groove
using the
cue control.
Check setting, correct if
necessary. Tighten
tension lever
(62) clockwise. Operate cue
control ( )
and bring back tonearm manual—
ly on
the rest. Lower cue control ( I ).
Connect unit plug to power line. For automa—
tic adjustment of the mechanical gear and
the shut—off mechanism the unit should be
started for the first time with the tonearm
locked.
Adjustment Point:
Knob (64) should not be movable when ten—
sion lever (62) is tightened. Adjustment
can be made after loosening machine screw
(229) and
sliding or shifting adjustment
plata
(228).
Fig.
13
48
49
38
206
210
207
212
226
Anti-Skating
Device
To
compensate for
skating force use
the
knurled
ring (66). The asymmetric cam plata
(68) displaces the
skating
lever
(237) from
the tonearm pivoting
point. The anti—skating
force is transmitted to the segment
(230)
and to the tonearm (50).
Optimum adjustment is carried out at the
works for styli with a tip radius of 15 µ
(conical), 5/6 and
18/22 µm (elliptical),
and CD 4—cartridges.
Any alteration can
only be carried out with
the aid of a Dual —Skate —O
—Meter and a test
record and should only be done by an autho—
rized service station.
Fig.
14
Anti—skating
68 237
230
238
13