Dual CS 731 Q - Motor and Drive Systems; Replacement of Motor Electronic System; Replacement of Mechanical Motor System; Speed and Pitch Control

The
set
value
necessary
for
the
45
rpm
speed
is
generated
in
the
voltage
divider
by
alteration
of
the
divider
ratio.
For
pitch
control,
а
continuously
variable
control
signal,
with
which
the
control
loop
is
fed,
is
obtained
by
means
of
a
complicated
division
pro-
cess.
Thus the complete control range, like the nominal speeds, is
coupled in a locked-phase relation to the quartz oscillator. The
speed accuracy in the pitch range is practically the same as in the
case of nominal speed. The speed deviation preselected with both
pitch controls is maintained even if the pitch switch is operated
or if the unit is seitched off.
In the speed logic, the display unit of the CS 731 Q obtains from
the actual speed the basic information as to whether the actual
speed of the nominal speed is faster or slower. A further logic sy-
stem activates the plus or minus sign of the display unit. Both
signals are dark at rated speed.
From the digital information on the actual speed, a further
digital /analog converter receives relative and analog information
which is transformed in the cascade switch to an activation voltage
for the 13 digital displays. In the display itself the information is
still completely analog as the individual digits are activated with
differentiated voltages and light up accordingly.
This display is as accurate as it is practical. The power section
supplies the various partial circuits with carefully filtered and
stable operating voltages.
General
The listed item numbers refer to the following spare parts lists
and exploded views.
The cover can be easily withdrawn from the hinged splice pieces.
To
remove
the
turntable,
remove
both
fillister
head
screws
(98)
and the discs (86) with which the mounting plate (197) is screwed
down.
The
turntable
can
be
lifted
out
of
the
bracket
(12)
after
disengaging the three transport locking screws.
Now detach the following plug connections:
1)
Both
single-pole
plugs
(722)
on
power
switch
(106).
2)
The
4-pole
plug
(160)
on
the
solenoid
protective
circuit
(185).
3
The 5-pole female multi-point connector (158) at the display
unit
(35).
4
The 5-pole female multi-point connector (185) at the distri-
butor board (24).
Fascia
To dismantle the fascia, remove both attachment screws (21)
with which the display unit is mounted on the bracket base.
bracket base.
The top of the plate (17) is attached with 3 fillister head screws
(98) and three washers (86) and the bottom is attached with
three cheesehead screws (50).
Fig. 4
Motor and drive
Special
tools
and
measuring
instruments
are
necessary
for
repair
of the Dual EDS 920. Therefore,
work on the motor or the motor
electronic
system should only be carried out by an authorized
Dual service station.
Replacement of the motor electronic system, complete
The
individual
modules
(151/152/153)
are
plugged
into
the
main
board. In addition, they are held by means of supports (154).
Moreover, module 1 is also secured with the fixing screw (159).
When replacing the complete motor electronic system, proceed
as follows:
1) Remove the fillister head screws (97) and the four supports
(154).
2) Remove fixing screw (159) (module 1).
3) Detach the plug connections fo the connection cable — refer
to wiring diagram Fig. 3.
4
Detach the motor electronic system completely from the
mechanical system of the motor and replace it.
Replacement of the mechanical system of the motor
1) Release both threaded pins (19) and withdraw plate cone (22).
2) Remove the complete motor electronic system — see above.
The plug connections of the connecting cable need not be
removed.
3) Remove both fillister head screws (99) and the cog (105).
4) Withdraw the mechanical system of the motor and replace it.
Fig.5
97
14
14
Pitch control
With the pitch control, each of the two rated speeds, 33 1/3 and
45 rpm, can be varied by + 5.5 96. With the seesaw switch (16) at
"ОМ" position, each nominal speed can be altered by means of a
separate potentiometer (14). At the same time, the optoelectronic
display scale (35) indicates the percentage deviation from the
nominal speed.
Independently of the potentiometer setting (14), the speed cor-
responds
with
quartz
precision
to
the
respectively
switched
no-
minal speed, if the seesaw switch (16) is in “OFF” position.
Stroboscope
The
stroboscope
markings
on
the
turntable
edge
are
flashed
from
the diode plate (148) by means of quartz accurate
frequency.
The display
is independent
of power frequency
and does not re-
quire additional
stroboscope
markings
for different
speeds and
line frequencies.