Dual 721 User manual

Dual
August 1976 Edition
721
Service Manual
Dual Gebrüder
Steidinger
•
7742
St.
GeorgenISchwarzwald
Download from www.dual.de
Not for commerical use

Specification
Current Type
AC 50 - 60 Hz, without
motor changeover
Line voltages
110 — 130
Volt, 220 — 240 Volt
Drive
Electronically-controlled direct drive System Dual
EDS 1000-2
Power Consumption
approx. 2.5 Watt
Motor during play <50 mW
Current Consumption
with 220 V 50
Hz:
on start-up 60 mA
during play 20
mA
with 110 V 60
Hz:
on start-up 110 mA
during play app. 38
mA
Run -up Time (until nominal speed is reached)
2 — 2.5
sec. on 33 1/3
rpm
Platter
Non-magnetic, dynamically-balanced, detachable, 1.5 kg
305 mm
Total rotating mass
of drive system (rotor with platter)
3.0 kg, moment of inertia 250 kp cm 2
Platter Speeds
33 1/3 and 45 rpm, electronically
switchable, automatic
tonearm lowering
coupled to speed change.
Pitch Control
Separate for both speeds, adjustable in each case with
variable resistor, with setting scales, range of adjustment
10 %.
Speed Check
with l ight stroboscope for platter speed 33 1/3 rpm.
Sensitivity of Light Stroboscope for 0.1 % Speed Deviation
3 graduations per minute at 50 Hz
3.6 graduations per minute at 60 Hz
Overall Speed
Variation
(assessed in accordance
with DIN 45 507)
<±
0.03 %
Signal-to-Noise Ratio
(in accordance with DIN 45 500)
Rumble unweighted signal-to-noise ratio
> 50
dB
Rumble weighted signal-to-noise ratio > 70
dB
Tonearm
Torsion resistant, extra long tubular aluminum tonearm
in super flat universal
four-point gimbal suspension, tone -
arm
balance weight with double acting
vibration
damping
(2
anti-resonators).
Effective Tonearm Lenght
222 mm
Offset Angle
25 0
20'
Tangential Track Error Angle
0.16
0
/ cm
Tonearm Bearing Friction
(related to stylus point)
Vertical
<0.07 mN
(0.007
g)
Horizontal <
0.15 mN
(0.015g)
Tracking Force
0 - 30 mN (0 - 3 grams) infinitely variable with 1 mN
(0.1 g) calibrations from 0 to 15 mN (0 to 1.5g), operable
from 2.5 mN (0.259) stylus pressure up.
0
-3
g continuously
variable, with 1/10 calibration in the
range from 0 - 1.5g, reliable as
from 0.25 g tracking force
Pick -up Head
Detachable, suitable
for all pick -up cartridges with 1/2"
mounting and a
deadweight of 2 - 10 g (including moun-
ting material)
Adjustable
Overhang
5 mm
Pick -up Cartridge
See separate data sheet
Weight
7.8 kg
Dimensions and
Cutout Required
refer to
Installation Instructions.
1976
2

Fig. 1
Circuit
diagram
Aug
Dual
IC1
22 n
0,7V
Strom
meßbrücke
Current measuring
bridge
Pont de mesure de
courant
• •
Ti
BD
135
20V -
Änderungen
vorbehalten
Alterations
reserved
Sous
reserve de
modifications
1
T2
BC 252 B
D7
ZPD 15
D 6
1 N 4001
13 14
R6
270
C
4.
1=2 50 bi
D8
ZPD
7,5
ED
Leerlaufstrom
ca. 55 mA
Icile
current
Courant ä vide
Anlaufstrom 255
mA ± 10 mA
Initial current
Courant de demarrage
R5
130
B
R 22
100 k
(33 1/3
Upm)
C)45Unm
33
1/3
1/3 lipm
7R4
470
C 51
— 0,068 µ
D 51
BY
183
300
R 51
22 k
Gl. 1
R 52
2,7 k
C 52
—
0,047
bi
220
V
T 0,125 A
Ce ° 0-•-
R
9
100
D9
AA 143
BIM
110/130V
220/240 V
Spannungen
gemessen
mit
Meßinstrument (7 — 10 MOhm Eingangswiderstand)
gegen Masse
Voltages measured with
measuring instrument (7 — 10
MOhm input resistance) to
ground
Tensions
mesurees avec
instrument de
mesure (7 — 10 MOhm resistance d'entree) contre
masse
51
1
2 3
4
9
27
8
51
52
3

S
1000-2
•
BC 338
T 4 BC 338
1
T 5 BC 338
D 10
AA
143Z
C 5
c + =I
1,5i
R16
68
D 11
AA
143'
Von der
Bestückungsseite gesehen
As seen frorn the top side
Vu du cöta elements
50 — 60
Hz. 8
14
0
1 2
7
1
R25
R26
220
2,2 k
BC 338
c;
C7
1 µ
± 10%
•
R 28
1 1
M
6-11
0,15 bt ± 10%
10
•
A
•
6
J 001
741
11
4
R29
22 k
•
R 30
77 013
820k
1 N
4148
C9
10/1 ± 10%
1
C8
47/1
+
50 % - 10
R 27
10 k
T8
BF
245 C
T9
BC 172 B
R 31
1
M
Drehzahlschalter
Platter speed switch
1 Commutateur de
vitesse
0
45
Upm
331/3
Upm •
R20
910
R18
'R33 'R21
220
1k 2,2k
(45
Upm)
Transistoren von
der
Anschlußseite gesehen
Transistors as
seen from the connecting side
Transistors vus du cötä des
connexions
E C D(4 ,
ib)G
•
BC 172 B
BF
245 C
BC
252 B
BC 338
1 1-r a
BD
135
B
C
E
R 32
33 k
Ausgabe
1/März
1976
23
16,24
25 26
28 27
14,13
15 17
18 33
30,21 20
19
31
32
5 9 7,6
8
4

Contents
Specification
Circuit Diagram
Dual EDS 1000-2 Electronic Direct Drive System
Description of Function
Speed Regulation
Page
2
3,4
6, 7
8, 9
9
Assembly I nstructions for
Dual EDS 1000-2 10
Stroboscope
10,
11
Pitch Control
11
Adjustment
of nominal speeds
11
Tonearm and Tonearm
Suspension
12
Removal of tonearm from
bearing frame
12
Removal
of tonearm assembly
vvith tonearm bearing
12
Replacement
of spring
housing
13
Adjustment of
tonearm
suspension
13
Vertical Tonearm Control
13
Antiskating
Control
13
Tonearm Control
14
Cue
Control
14
Replacement of
cue control assembly
14
Starting
15
Manual Start
16
Stopping
16
Muli ng
switch
16
Continuous Play
16
Pick -up head not paral lel to platter
16
Shut-off
17
Stylus slips out
of playing groove
17
Tonearm does not set down at the edge
of the record 18
Tonearm does not set down
or lowers onto record too
quickly
18
Vertical
movement of tonearm
dragging 18
Tonearm
returns to rest immediately
18
Tonearm moves
with dials in zero position
18
During
automatic
operation
of tonearm disturbing noises
are perceptible
18
Motor does not shut-off
18
Acoustic feed back
18
Pick -up Connection Diagram
19
Spare
Parts
20
Exploded view - Parts above chassis
21
Exploded view - Parts below chassis
22
Spare Parts
23 -
25
Lubricating I nstructions
25
Note: The
reference numbers in the
instructions refer to the spare parts lists and
exploded views.
5

Fig. 2
Dual EDS 1000-2
Electronic
Direct Drive System
turntable center plate
centering pin
ring
magnet
steel
plate
conductor
coil
support
plate
field
coi l ls
heddecl
Hall generator
Dual EDS 1000-2
Electronic Direct Drive System
The EDS 1000-2 motor
especially designed
for the Dual 721 is a slow-running no-commu-
tator DC electronic motor which
draus
its
power supply from a
stabilized power pack.
The electro-mechanical
commutation normally
carried out
an
DC motors by the
commutator
is electronically controlled in the case of
the Dual EDS 1000-2 motor by two Hall genera-
tors. These two Hall
generators - dependent
an the rotor position - control four switch-
ing transistors which in turn have the
effect of a rotating
magnetic field occurring
in the field coils of the
motor by means of
which the four pairs of magnets
of the rotor
are continuously attracted or repelled. By
means of the torque thus exerted, uniform
rotation is
induced in the rotor - and with
it the platter.
A
speed-dependent voltage (tacho voltage)
induced in the motor windings not
switched
an is coupled out and controls
the electro-
nic regulator circuit. This
ensures that
even the
slightest deviations from
the nomi-
nal speed are corrected in fractions of
a
second by a change in
the motor current.
Speed
fluctuations are, therefore,
practi-
cally eliminated.
joining centring
for turntable
rotor
plain
bearing
flange
angular bearing
Absolute
maintenance of
the nominal
speed
na langer
presents any
problem with this
control
system.
The
above-mentioned Hall
generator
is a mag-
netically
controllable
semi-conductor ele-
ment
named after
the
physicist E.
Hall. With
the Hall
effect as a
result of the
action
of a
magnetic
field an the
Hall
generator a
voltage
approximately
proportionate to
the
strength
of the
magnetic field
is
generated,
its
polarity being
dependent
an the
direc-
tion
of the
magnetic
flux.
A
control
current
flows
through the
Hall ge-
nerator.
If now a
magnetic
field
becomes
effective at
right
angles to the
area of
the
Hall
generator,
the
so-called Hall
voltage
occurs. With
constant
control
current this
Hall
voltage is
dependent
an the
direction
and
strength of
the
magnetic
field. If the
polarity of the
magnetic
field is
reversed,
the
polarity of
the Hall
voltage
changes as
well.
In the
absence of a
magnetic
field the
Hall
voltage is
zero. This
effect is
utili-
zed to
control the
Dual EDS
1000-2 motor.
As
the motor
is operated
on DC from
a stabi-
lized
power
pack it
operated
independently
of
line
voltage and
frequency
fluctuations.
The motor
is of 8
-pole disk
rotor
design.
The
rotor has a
barium ferrite
annular mag-
net inside
which has 8 -pole
magnetization
an
its lower
face.
6

A
slotless steel disk connected to
the rotor
acts as magnetic return.
The field windings of the
motor are ironless
and are embedded in
a plastic support. The
field
windings consist of 16 double wound
coils which are arranged in
two planes above
one another. The 8
coils of the lower plane
are 22.5 0 offset in relation
to the top pla—
ne. In each plane there
is a Hall generator
in the center of one
coil. The two Hall ge—
nerators are also
offset by 22.5
0
in rela—
tion to one another.
The individual
windings — 32 in all — are
connected
together so that four all round
phase windings
are produced.
Compared with other
directly—driven record
players in
the case of the Dual EDS
1000 mo—
tor no form of magnetic
drag or restoring
force is present
(pole jerk etc.) as can
easily be detected
by turning the
rotor. As
a
result of the
ironless field coils no
hy—
steresis or eddy
current losses or
interfe—
ring slot—ripple
frequencies
occur.
This
results in
completely
vibration—free
motor running
together with a
low power con—
sumption of
less than 50 mW
during play
(the
electronic
system is
not taken
into account).
By
virtue of
this
vibration—free running
the
motor can be
rigidly connected
to the chas—
sis. The
electronic
system
itself is
divided
into the
switch,
commutation and
control
sections
(see block diagram).
Fig. 4 Block Diagram
110-130 V
220-240 V
50-60 Hz
Supply unit
Netzteil
low ]
Gleichrichter
Rectif ier
Bloc secteur
Redresseur
Stoboskop
Elektronik
Strobe
Electronic
Stroboscopique
Electronique
Fig. 3 Line Board (Equipment Side)
Glimmlampe
Glim
lamp
Lampe
ä
effluves
Stabilisierung
Stabilization
Stabilisation
Netztran
sf ormator
Mains transfor mer
Transforrnateur de
riseau
• •
C 52 0047
II
.-ti-•
L___. D51
er iesmo,
Ill- Til
3 eo 68i;
9 - 1R51/22K I--•
T125mA
0
220 110V
Schalt- und
Regelteil
Switch and
control unit
Circuit et
pike- - 11---
de räglage
I
e e
220V/ SO -60
Hz
Drehzahlum-
schaltung und
Feinregulierung
Speed change et
fine
tuning
Changement
de
vitesse et
accord
präcis
7

Desuiption of
Fumion
The 4 phase windings are each in the
collec—
tor
circuit of the 4 switching transistors
T 4 to T 7 (Fig. 5) and are connected
to—
gether in star form at one
point. This point
is connected to the
minus pole of the supply
voltage.
The position of the rotor illustrated in
Fig. 6 has the
effect that the magnetic
field of the south pole of a
pair of poles
at connection 11 of the Hall generator H 1
gives rise to a Hall voltage maximum of ne—
gative polarity.
Transistor T 4 whose base is joined to con—
nection 11 of the Hall
generator therefore
receives a
negative base
emitter voltage and
is fully connected through whereby
the cur—
Fig. 5
Fig. 6
-14V 0
rent
flows through the
phase winding W 1
lo—
cated in the
collector
section or
it is
switched on.
Transistor T
5 whose base
is joined to
con—
nection 9 of
Hall
transistor H 1 is
blocked
by the
positive Hall
voltage potential.
As
Hall generator H 2 is
in the neutral zo—
ne
of the pair of
magnetic poles during
this period, no
Hall voltages occur at its
connections 7 and 5.
The transistors T 6
and T 7
joined to these
connections are,
therefore,
blocked as well.
The switched
on phase winding W 1 (Fig. 7
a)
produces clockwise rotation
of the rotor
through 22
1/2°. This cycle takes
place,
displaced electrically
in each case by 90
0
,
in
sequence in all four
phase windings.
7
T3
12
W1
2
D9
4
•
D102
T5
T5i
5
21311
W4 j
D122
H2
N z'
-,
-
N
,
\
N ‘ 1- 1 1
iiii ii it
H1

6
6
Thus the following sequence
of movement ta-
kes place:
After the 1.
rotation phase (Fig. 7 b) the
Hall generator H 1 is located in the neutral
zone of a pair of magnetic
poles. One south
pole is now directly
above Hall generator
H 2 and now also produces at its
connection
7 a Hall voltage maximum
of negative polar-
ity
which switches on phase winding W 3 via
transistor T 6. All other transistors are
blocked. The rotor now rotates again through
22 1/2 0 through the magnetic fields genera-
ted in
phase winding W 3.
After elapse of the second rotation
phase
(Fig. 7 c) the Hall generator H
2 is now in
the neutral zone of
a pair of magnetic po-
les. Hall generator H 1
is now directly un-
derneath a north pole and a
Hall voltage of
reversed
polarity occurs, i. e.
the negative
polarity
Hall voltage maximum is
now present
at connection 9 which
connects through phase
winding W 2
via transistor T 5.
The other
transistors are
blocked. The rotor
again advances by 22 1/2°.
After this 3.
rotation phase (Fig. 7 d)
Hall
generator H 1
is in the
neutral zone. A
north pole
is above Hall
generator H 2 and
produces a negative
Hall voltage at
its con-
nection 5
which switches
on phase winding
W 4 via
transistor T 7.
The rotor
advances
by a further 22 1/2°.
After
conclusion of this 4.
rotation phase
the process starts again.
Thus, a continuous
rotating field
occurs which drives
the rotor
at an uniform
rate.
If the
rotor is, for
example, between two
phase windings, a
partial flux of a pair of
magnetic poles passes
through both Hall
ge-
nerators and thus two
switching
transistors
are partly
opened. The
current
is divided
accordingly between two
phase windings. Both
phase windings
participate
simultaneously
in the
torque formation and
together produce
the
torque of a
fully-connected phase um -
ding. The torque is,
therefore, almost
con-
stant in any position of the rotor.
Speed Regulation
As a result of the rotary movement of the
rotor, voltages are induced in the
phase
windings not connected through
which are
coupled out via diodes D 9
to D 12. Thus, a
tacho voltage proportionate to the speed is
obtained.
The tacho voltage passes via a voltage divi-
der to connection 4 of the
operation ampli-
fier in the control section and counteracts
the voltage present there. A stabilized vol-
tage is
present at connection 5 of the
ope-
ration
amplifier.
On start-up and during run-up of the motor
the potential at connection 4 of the
opera-
tion amplifier is more or less positive in
relation to
connection 5. In this condition
the operation amplifier fully drives tran-
sistor T 7. T 7 is present as variable
re-
sistance in the common emitter circuit of
the four switching transistors
through which
practically the full switching current can
flow in sequence.
Fig. 7
Robar
zwejam -
H2
HI
H2
H1
W3
H2
H2
-1ZIN
HI
2
HI
W4
The nominal or controlled speed is reached
when the same potential is present at con-
nection 4 of the operation amplifier as at
connection 5, because at this moment the
operation amplifier closes transistor T 7.
As a result the motor current drops and
the
speed cannot, therefore, increase any fur-
ther.
By
switching over or altering the voltage
divider in the control circuit the controlled
speed can be
preselected or altered. With
reducing speed the potential at connection
4 of the operation amplifier would change
so that
transistor T 7
would
be
fully
driven.
T 7 would thus become of low resistance, the
result would be
a sharp rise in the motor
current and thus of the speed.
As this control process takes place
even at
minor deviations from the
nominal speed, a
constant speed independent of
load fluctua-
tions is obtained.
9

Assembly
lnstructions for Dual
EDS 1000-2
For
repair
of
the Dual
EDS
1000-2
special
tools
and
measuring
means are
required.
Work
on
the
motor or
motor
electronic
Sy-
stem
should,
therefore,
only be
carried
out
by an
authorized
Dual
service
station.
Ex-
penses
arising
from
unauthorized
interferen-
ce
will be
charged to
the
consignor.
Removal
Lift off platter (4). Remove
housing of p0 -
wer pack (123) after removing screws (117).
Fig. 8
125)--
6
Attention! Unsolder leads for operating vol-
tage on power board (125).
Do not remove
cable on motor side.
Unsolder connections on rotary
knob (192)
and potentiometer (191/R
33). Pull off in-
sulating tube.
Unscrew complete
bearing pillar (147) and
remove together
with washer (148). Remove
cam wheel (144). Be careful with ball (136)
in stop bar (164). Remove intermediate pla-
te
(137).
Undo hex nuts (75) and the three machine
screws. Lift motor (5) and make sure that
the connecting leads and the
thermistor are
routed in the chassis
recessed. Remove the
motor. Slide the
insulating tube over the
connecting leads. Place motor in original
carton for return shipment.
Installation
Remove motor
from packing, pull off insulat-
ing tube. When inserting the motor on the
mounting board (21) ensure that the lead
outlet
hole faces the power pack (123).
Now, refit motor and other disassembled
parts in reverse order to that
described
under "Removal".
Attention: To prevent deformation of the
shorting springs the camwheel (144) should
not be fitted in 0 position. Make sure that
the pin of main
lever (154) is engaged in
the guideway of the camwheel (144).
After assembly fit knob (44) complete with
pin in midposition. Switch on unit and check
current
consumption on operation.
220 8/50 Hz approx. 18 mA
117 V/60
Hz approx. 35
mA
Using
control (R 21) set nominal speed
45 rpm (check by means of a
strobe disk),
using control (R 22) set nominal speed
33 1/3 rpm. Run in for approximately 5 mi-
nutes and,
if necessary, correct speed.
Note:
lt
is advisable subsequently to
carry
out a brief check of all unit functions.
Stroboscope
Accurate
setting of the platter speeds
33 1/3 and 45 rpm can be
checked during
play with the aid
of the stroboscope.
When the platter (3)
is rotating at
exactly
33 1 / 3
or 45 rpm the lines of
the strobos-
cope appear to stand still. If
the lines
move in the direction of
rotation of the
platter, the platter
speed is too high. If
the lines move
backwards, the platter
is
rotating more
slowly than the nominal speed.
Adjustment of platter speeds 33 1/3
and
45 rpm is carried out
separately with the
"pitch"
knobs (44).
10

6
lt can happen that the stroboscope lines
appear to
move slightly although the exact
speed setting with stroboscope lines sta—
tionary has not been altered. This
apparent
contradiction is explained by the
fact that
the electronic
central drive motor operates
fully independently of line frequency whilst
the only
relatively accurate line frequency
of the AC current supply is used for speed
measurement with the light
stroboscope. The
constantly
detectable fluctuations of line
frequency by +
2 % (according to the infor—
mation of the electricity supply companies)
brief
frequency fluctuations up to 1 % arm
possible — only effect the
stroboscope in—
dication and
can cause the lines to "wander"
although the platter speed is
am constant
and absolutely accurate am before.
Strobe markings are
provided on the outer
edge of the platter
for 50 and 60 Hz line
frequencies.
To replace glow
lamp (103) remove
machine
screws (105) and remove strobe
cover (104).
Pitch
Control
Each
of the
two standard
speeds 33
1/3 and
45 rpm can
be varied by
approximately 10 %.
The
variable speed
control (R
33) located
in the
voltage divider is
adjusted
by turn—
ing the pitch
control
knob (44). By
this
means the
operation
amplifier is
altered
and the
motor
speed
accordingly.
Adjusting
the nominal
speed
Using knob (44) bring the variable speed
control (191) into
midposition.
Nominal
speed 33 1/3 rpm using R 22 control
Nominal
speed 45
rpm using
R 21 control
Check with
strobe disk.
Fig. 9 Stroboscop
Fig. 10 Pitch
control
11

Fig. 11
Tonearm suspension
28 27
41 201 72
50
40
53 58 48 36 54 38
____•_•_,.
BIS IZ 311111 MM Mir ......
Tonearm and Tonearm Suspension
The
feather-light,extremely torsion
resi-
stant
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
friction vertical
0.007 p
Bearing friction
horizontal 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
carried out by
moving the
weight with
the
stem
(51), the
subsequent fine
adjustment
by turning the weight.
The balance
weight is
designed so
that pick -
up
cartridges having a
deadweight
of 4.5 -
10 g
can be
balanced. lt takes
the form of
a
double
anti-resonator
thus
absorbing the
vibration
energy in the
range of
tonearm
and
chassis
resonance. For
this purpose,
the
inner
part
weight is
matched to
the
tonearm
Fig.
12
58
53
50
62
64
233 -
210
159
;Jlio e
1 1.1
,017136.9
111.T7=11411
;..
lenni
•
moullY
11.
230
231
232
214
234
156
38
54
55
51
111H11
111111111111111111
sommulan
resonance and
thus acts as anti-resonator
by means of antiphase
vibration. 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
(58) incor-
porating
a coil
spring. The
scale has
mar-
kings for a
range of
adjustment
from 0 to
30 mN
(0 to 3 p)
which
permit
accurate ad-
justment of
the
tracking
force. One
grad-
uation 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 (50)
from
bearing frame
1. Secure
unit in
repair jig.
Remove weight
(51)
unscrew
fixing screw (54).
Set
tracking force
scale to
zero.
2. Move unit
screening
an muting
into head
position.
Remove
plate
(133). Unsolder
tonearm
switch
(131).
3.
Move unit
into normal
position.
Turn
both
mounting screws
- SW 4.5 -
(55)
counterclockwise to the
stop of the
bear-
ing
frame
(53).
Attention!
Observe the
bayonet
mounting.
Slide
tonearm (50)
rearwards
and remove
it
upwards
from the
bearing
frame.
For
installation
proceed in
the reverse
or-
der.
Removal of
tonearm
assembly with
tonearm
bearing
Proceed as
follows:
73
1. Secure
unit in repair
jig. Set
graduated
spring
housing (58) to
zero. Arrest tone -
arm
(50). Remove
weight
(51).
2.
Loosen
tension layer (62)
and bring
tone -
arm (50)
in its
highest
position using
knob (64).
Fasten
tension lever (62).
Bring
knurled
ring (66) in
position
"3".
3.
Turn unit
upside down. Remove
screening
plate (133).
Unsolder
tonearm leads on
the
muting
switch.
4.
Remove machine
screw (217), hex
nut (218)
and
fillister
head screw
(70). Also re-
move transition plate
(268) and guard
plate (219).
12

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

Recheck as follows:
Balance
tonearm (50) correctly. Set knurled
ring to 0. The tonearm should
remain at any
desired point within its turning range. The
hole of the skating
lauer (237) should be in
alignment with
the center line of the
tone —
arm. Adjustment
is made by the eccentric
pulley (E) which
is accessible through the
hole in the installation plate (21) between
the knurled
ring (66) and the tonearm
mount—
ing plate (71). See Fig. 14.
The set knurled
ring to "0.5". The
tonearm
should now
smoothly rotate from the
platter
center to its
rest.
Tonearm
Control
Automatic movement of the tonearm is ini—
tiated by the control cams on the inside of
the cam wheel (144) on rotating through
360 0 . The
control elements for raising and
lowering
are the control layer (154), the
main lever (156) and the lift pin (47), for
horizontal movement of the tonearm control
lever (154), the main lever (156), the
coupling plate (233) and the spring pin of
the segment (236).
The automatic set—down point is designed
for
30 cm and 17 cm records and coupled to the
platter speed
changeover.
Fig.
15
Cue
control
144
1 4 170
159 F 246 237
133 152 161
153 156 189 230
Limitation of
the horizontal
movement (set—
down point) of the
tonearm is
produced by
the pin of
segment (230)
contacting the stop
(189) attached to the slide
bar (246).
Only during
set—down does
main
lever
(156)
lift the slide bar
(246) and the stop
(189)
attached to
it which, as a
result,
moves in —
to the
swivel range of the
stop pin fitted
on segment (230).
On completion of
set—down
(lowering of the
tonearm onto the record)
slide bar (246) is
released again and re—
turns to its
neutral
position.
As a
result,
stop (189)
moves out of the
swivel
range of
the stop pin
(F) so that
unimpeded movement
of the
tonearm is possible for
playing.
Cue
Control
By moving the lever (201) forward ( ) lift
cam (203) rotates. The slide bar (246) con—
nected to it transmits this movement to the
lift pin (213) (via the compensating cam)
which then
raises the tonearm.
As
a result, the.cue control permits set—
down of the tonearm
at any desired point.
The slide bar
(246) is released by moving
the cue control lever
rearwards ( I ). As a
result of the action of compression
spring
(212) lift pin (213) is returned to neutral
position
and thus lowers the tonearm. Lower—
ing of
the tonearm is damped by silicone oil
in the
lift tube. The height of the
stylus
above the record
can be varied by turning
adjusting screw (44). Turning bush (207) to
">"
reduces the lowering speed, turning the
bush to ">--->" increases the lowering speed.
The
distance between the record and the sty—
lus can be varied by set screw (40).
lt
should be approx. 3 to 5 mm.
Fig.
16 Replacement of Cue Control Piste
Replacement of Cue
Control Plate
Replace cue control plate (210) as follows:
1. Fix unit on repair jig and lock tonearm.
Remove
weight (50). Turn unit
upside
down.
2. Loosen tension lever (62), bring tonearm
in its lowest position using knob (64).
3. Set knurled ring (66) of the
anti—skat—
ing device to
position
"3".
4.
Remove machine
screw (217),
hex—nut
(218)
and
fillister head screw (70).
Remove
transition plate (268) and guard plate
(219).
5.
Remove safety washer (152) and axle
(161).
Also
remove main lever (156) and com—
pression
spring (155).
6.
Remove
countersunk screws (234) and coup—
ling
plate
(233).
7. Loosen
safety washer (222), then turn
set screw
(40) until slide bar is re—
leased.
Place slide bar (246) complete
with bearing (211) beside the bearing
pin.
14

8. Remove compensating cam
(226) and com—
pression spring (225).
9. Undo pin (214). Turn bush (207)
to " ".
Remove cue control plate
(210) from cam
(223). The turn until the
bush (207) fits
the recess of
the mounting plate
(128) so
that the cue control plate (210)
can be
removed.
For installation proceed in
reverse order.
Adjustment points
a) Disconnect unit
plug from power line
(mains). Move
lever (74) to
"start" po—
sition. Rotate platter (4)
until the to—
nearm has reached its
highest position.
The
distance between the lower edge
of
the pick —up head (27)
and the rest (41)
should be
approximately 3 mm. Adjust
by
turning bush
(206) (Fig. 17).
b)
Disconnect unit
plug from power
line.
Lock
tonearm (50). Move
lever (74) to
"start" position.
Rotate
platter (4) and
observe shaft
pin (235) of the
coupling
plate (233). The
guide lauer
(235) on the
main lever
(156) should
just tauch
the
shaft pin
or just move
lt by 0.1 mm
(ad—
justable by setting
machine screw
(158)
(Fig.
18).
Starting
Change lever (174) is
rotated when the left
control lever is turned
to "start". This
results in the following function
being ini—
tiated.
The control arm (170) connected to change
lever (174) operates
the power switch which
starts the motor (5) rotating. Simultaneous—
ly, pawl coupled to the change
lever (178)
by a tension spring engages
and retains lt
in this
position.
The change lever
(178) presses the shut—off
lever (142)
toward the dogs on the
motor
pinion and thus causes the camwheel (144)
to rotate. The pawl
then moves - deflection
lever (139) into
starting position.
After fitment and each time
after transport
the unit should be started once with the
to—
nearm locked for
automatic adjustment of the
mechanical gear.
Adjustment points:
a)
Place unit upside
down.
Disconnect power
line plug until
detent (164) is
secured.
Slightly
move cam (144) out
of position.
The
play between
the detent
(164) and pin
(8)
should be about
0.3 mm (see Fig.
21),
Correct
setting by
bending switch arm
section (LS).
b)
Disconnect
unit plug
from power
line.
Place unit
upside down.
Operate control
lever
(74).
Rotate motor.
The power
switch
(106)
should operate
shortly be—
fore the
change lever
(178) catches. Ad—
justment
should be made by
turning
eccentric
pulley "E".
c) Tonearm
(50) should lauer
the stylus
exactly
on the lead—in
groove. The ad—
justment
screw is accessible
through the
hole between
control lever (74)
and the
cue control.
The adjustment
screw should
be
either turned
clockwise or
counter—
clockwise.
Fig.
17
3mm
Fig.
18
1
154 129 158 157 159 233 235
153 152 156
230
215
d) The
change lever (174)
should bring de—
flection
lever (139) into the
start po—
sition.
Adjustment
can be made by
slight bending
of change lauer
section (U).
Fig. 19
Starting
15

Manual
Start
The detent (164)
coupled to control arm
(170) engages
the pin in the chassis when
the
tonearm is moved inwards by
hand and re—
tains the tonearm in this
position (Fig. 21).
The power
switch is operated by the
control
arm and thus
the platter starts to rotate.
After
reaching the run out groove of the
played record return of the tonearm and
shut—off of the unit take place
automatical—
ly. If, on the other, the tonearm is
lifted
off the record before playing is
completed
and is moved onto the rest by
hand, the pin
of the
segment disengages the detent (164)
so that the control arm is returned to its
starting position. As a result, the power
switch shuts off the power supply.
Adjustment point
Extract power plug. Turn unit
upside down.
Move tonearm
inwards. Power switch should
switch
safely. Correct adjustment
by bending
control arm (0.
Stopping
When control lever (74) is set
to "stop" po—
sition the change lauer (174) is turned an—
ti—clockwise. The deflection lauer (139) re—
mains in its stop position.
Muting
switch
To prevent disturbing noises
during automa—
tic
operation of the tonearm the unit is
fitted with
a muting
switch.
Control of the
switch springs for both
channels is effected
by the camwheel.
With the unit in neutral
state the short circuit of the pick —up
leads
is eliminated.
Adjustment
point
In
neutral position the
distance between
contact
springs should be about
0.3 mm.
Correct by
slightly bending contact
springs.
Continuous
automatic play
The continuous automatic play
is operated
by turning knob (72) to "00". Switch bracked
(242) is actuated by knob
(72). Switch rod
(241) keeps change lever
(174) in start po—
sition. After playing the record
the tone—
Fig. 20
Muting
Switch
arm returns
automatically to
the lead—in
groove of the
record. The
record will
be
played again.
This procedure
will be
repeated
until cancelled
by pushing
control lauer
(74)
to "stop"
or turning
knob (72) to
po—
sition "1".
Adjustment
point:
Bring
turning knob
(72) to
"00" position.
The
play
between the
eccentric pulley
(E)
and
change lauer
(174)
should be 0.1
to
0.3
mm. Adjust by
bending the
switch rod
(241)
(Fig.
19).
Fig.
21
170
164
Defect
Tonearm
head not parallel
to platter.
Cause
Seat of tonearm
head on the
tonearm tube
has
changed during
transit.
Remedy
Remove
platter. Insert
screwdriver
through
the hole
in the chassis
mounting
plate.
Align
tonearm head
and
retighten screw
(Fig.
22).
Fig.
22
16

Shut-off
Operation
Fig.
2L.
The
functions of
automatic set—down and
shut—off are
determined by the
position of
the
deflection lever
(139). The
deflection
lever (139) is
only moved
out of stop po—
sition during
starting by the
change lever
(174).
Initiation of
shut—off after playing
the record is
brought about by
the dog (M)
of the
motor pinion
and the
shut—off layer
(142).
The
shut—off lever
(142) is guided onto
the
dog by the
movement of the
tonearm when
playing the record
with the aid of
the shut—
off
bar (182)
proportionate to
the groove
lead. The
eccentrically—mounted dog forces
the shut—off
lever (142) back
with each re—
volution as long as the
advance of the to—
nearm only amounts
to the width of one
groove
(Fig. 24 a).
Only the run—out groove
with its increased
lead guides the
shut—off lever (142) onto
the dog at a
higher rate so that the shut—
off lever is
picked up and moved along
(Fig. 24 b). The camwheel
(144) is thus mo—
ved out of
zero position into engagement
with the motor pinion
(Fig. 18 c).
Adjustment
point:
With the
eccentric pully "S" on
segment
(230) the
shut—off point can be
varied.
Fig.
23
Shut—off
Operation
DefeM
Stylus slips out of
playing
groove
Cause
a)
b)
c
d)
e)
f)
g)
Tonearm is
not ba—
lanced
Tonearm tracking
force is too
low
Anti—skating
setting incorrect
Stylus tip warn
or chipped
Excessive bearing
friction in tone —
arm
bearing
Steel ball (136)
of shut—off bar
(182) missing
Friction of dog
of segment (230)
in guide piece
(215). (Segment
shifting when to—
nearm is in stop
position for 30 cm
records.)
MR M
142 143 182
Remedy
a)
Balance
tonearm
b) Adjust
tracking force to the
value stated
by
the
cartridge
manufacturer
Correct
anti—skating
setting
Renew
stylus
e) Check
tonearm bearings and
re—adjust if
necessary
f) Renew
steel ball
(136).
g)
Bond holding
spring p31) or check ad—
justment points "b"
Fig. 18, page
15).
17

Defect
Tonearm does not set
down at the edge of
the record
Tonearm
does not set-
down
or sets-down
too
quickly after
operating cue con-
trol lauer
(201)
Vertical tonearm mo-
vement shows resi-
stance during set-
down
Tonearm returns to
rest after manual
set-down immediately
after the
platter
starts to turn
Tonearm
moves with
tracking force and
anti-skating scale
in 0 position
a)
outwards
b) inwards
During automatic
operation
tonearm
disturbing noises
are perceptible
No reproduction. The
short circuit of the
pick -up leads is no
longer being elimi-
nated
Motor does not shut-
off
when tonearm
sets down on rest
Acoustic feedback
Came
a)
Record size set-
ting incorrect
b) Tonearm
set-down
point is incor-
rectly set.
a) Set screw (40)
maladjusted.
b) Damping excessive
or too
low by
contamination of
the silicone oil
Excessive
friction
of
lift pin (213)
in
guide tube
Position of shut-
off has altered dur-
ing transport of
the
unit
a) Anti-skating de-
vice out of ad-
justment
b) Excessively tight
tonearm leads
produce a torque
Muting
switch out
of adjustment. The
distances between
the slide springs
and the
short cir-
cuit strips
on the
muting
switch are
excessive.
Distance between the
slide
springs and
the
short
circuit
strips on the
muting
switch is
absent or
insufficient
Suppression
capaci-
tor
(111) in power
switch is
defective
(short
circuit)
a)
Chassis compo-
nents (e.
g. also
connecting leads)
b)
Connecting leads
are too
tight
Remedy
a)
Gerry out necessary
adjustment with the
control
lauer (74).
b)
Set control
lever (74) to
"33". The ad-
justment screw
becomes visible
through
the hole between
the control lever (74)
and the
cue control. Turn
adjustment
screw either clockwise or
anti-clockwise.
a)
Adjust set screw
(40) for 3 - 5
mm cue
control
height.
b) Using turning
bush set for ( - 22i)
or ( - 2).
If necessary,
remove cue control plate
(210), as described on
page 14 and also
remove shaft pin (204) on
the lift pin
(213), washer (205),
adjustment sleeve,
the
second washer (205).
Remove lift pin.
Clean lift tube
and lift pin.
Smear lift
pin evenly with
"Wacker Silicone Oil
AK
300 000".
Reassemble
components.
See above (b)
After fitment
and auch time after transport
the unit should be
started once with tone -
arm
secured for automatic
adjustment of au-
tomatic
shut-off.
a)
Adjust skating
lever (see p.
13/14)
b) Slacken
tonearm leads
By bending the short circuit
strips. Adjust-
ment is correct
when, with the camwheel
in
neutral position, the
distance between the
slide
springs and the short
circuit strips
on
the muting
switch is approx. 0.3
mm.
Spray
contact springs with
preservative
(e. g. Kontakt 61)
and check adjustment
of
short circuit
strips.
By
adjusting the short
circuit strips.
Ad-
justment
is correct when,
with the camwheel
in neutral
position, the
distance between
the slide
springs and the
short-circuit
strips on the
muting switch is
approx.
0.3 mm.
Renew
suppression capacitor in
power switch
(10.000
pF/700 V)
a)
Line up cutout in accordance with data
in
fitting instructions.
Move leads.
b)
Slacken or
lengthen cable
18

Fig.
25
Pick
—up
Connection
Diagram
right
channel
I
red
in
L _
—
, ,
- -
7 1
I
I
01
connection
plate
right
channel
red
Mass right channel
green
Mass
sheet
011
Contact plate at
tonearm head
Record
Cartridge-holder
red
green
Cartridge
inner side
of groove
left channel
L__
0
2
left
channel
white
r
0 2
_
_J
,-1
.)-
r
. :1- 7
3
,--
.
--K
,
i
1
i___
J
I I I
.>
-I
--
I
.., j
Tonearm audio cable
black
al with miniature plug 5-pin
right channel
red
lead
left
channel
white
lead
left
channel
white
___
1
b) with phono plug
I I I
I I I
black
white
(red)
(yellow)
Mass left
channel
blue
white
blue
outer
side of
groove
right
channel
Tonearm head
Spring contacts
between
plug-in cartridge
head and tonearm

Replacement
Parts
Pos. Part.
No.
Discreption
Qty.
1
220 213 Centering disc
CN
c-
•
CJ
(s4
e-
C
2 238
434 Washer
3 239 409
Turntable mat complete
4
239 410 Turntable
complete with mat
5 239 411 Electronic
direct
drive system
EDS 1000-2
compl.
7 210 516
Machine screw M 4 x 8
8 239 350
Washer 4.2/7/1
9 237 644 Supporting post
10
237 795
Dress plate
11
210 586
Washer 3.2/7/0.5
12
227 402 Fiat
head screw M 3 x 4
13 237 668 Special
screw
14
239 413 Dual emblem
15
200 444 Spring washer
16
239 414 Shipping screw complete
17
210 146 Lock
washer 3.2
18
201 632 Rubber washer
19
237 117 Washer
20
237 118 Lock washer
21 239
415 Chassis complete
22
234 432 Spring mount
compl. (Tonearm side)
239 416
Spring mount compl. (Sapply
unit
side)
23
230 529
Threaded piece
24
232 842 Compression spring (Tonearm
side)
238
556
Compression spring
(Sapply unit side)
25
200 723 Rubber damping block
26
200 722 Steel cup
27
239 417 Tonearm head compl
28
234 611 Handle
29
210 182 Bowed
lock washer
30 210 630
Washer 4.2/8/0.5
31 210 197
"C" clip G 4 x 8
32 236 242 TK 24 cartridge mount
33
236 896 Contact plata compl
34 237 671 Pointer
35 237 672
Pin 2 x 6
36 234 635
Lock nut
37 230 063
Grub screw
38 239 418 Frame compl
39 237 481
Tension spring
40 237
623 Turning knob
41 236
911 Tonearm rest compl.
42 210
362 Hex nut BM 3
43 218
321 Hex nut M 10
44
237 530 Turning knob compl.
45
237 661
Grub screw M 3 x 4
46
239 419 Cover front compl.
47
200 444 Spring washer
48
234
635
Lock nut
49 217
438 Grub screw
50 239 188 Tonearm compl.
51
239 420 Weight compl.
52
236
160
Supporting plata
53 239
421 Bearing rock
54 236 051
Clamp
bolt
55 234
617
Fixing screw
56
239 422 Bearing compl.
57 210 475 Machine screw AM 3 x 5
58 236 907 Spring housing compl.
59
237 563 Washer
60
237
564
Bearing screw
61 237 471 Shaft
62
237
581 Tension lever
63 234
303
Compression spring
64
237
577 Turning knob compl.
65 210 361 Hex nut M
3
66
237 618 Knurled ring
67
216
867
Bowed
lock washer 5.2/10
68
225 176 Curve washer
69 210 361 Hex nut M 3
70 237 737 Fillister
head screw
countersunk M
3 x 10
71 239 423
TA—Plate
72
237 544
Turning knob compl.
73 239 424
Cover complete
74 237 537 Switch layer
75 210 366 Hex nut BM 4
76 237 738 Fillister head screw
countersunk M 3 x 8
20