Seeburg 7800, Service Manual

Page: 24 / 87

SeMrice Manual '41 Models 7800, 7850, 8800 and 9800
guide plate (Fig.
25,
Item
9 ) .
When taking off t..l\e solenoid
guide plate the collector brush
blades must be unsoldered from
the leads that connect to them.
With the aid of a soldering iron
the defective solenoid may b e re­
moved a.no a new solenoid re­
placed. The solenoid guide plate
and selector disc may then be re­
placed and the collector brush
leads soldered to their respec­
tive terminals.
C.
MOTOR
C
O
N
T
R
O
L RELAY
The motor control relay
(Fig.
25,
Item
2)
should operate
when the solenoid �lunger and
stop pin are up or when the
motor carry-over switch is
closed. The motor control relay
receives its current from the
25
volt power transformer on the
amplifier or Master Control Sta­
tion. I t s contacts operate the
Symphonola motor. If the motor
control relay fails to operate,
the relay coil may be defective
or there may be
an
open circuit
in the power circuit or between
the solenoid plunger (Fig.
25,
Item
12)
and t.he plunger contact
spring (Fig,
25,
Item 13) . This
may be checked with a volt meter
capable
of
indicating approxi­
mately
30
volts A.C.
I f the motor control relay
operates and the Symphonola does
not start, the most likely
trouble in the relay would be
with the con tacts. Either the
contacts have insufficient pres­
sure or they may be dirty and
pitted. If the pressure is in­
sufficient, it should be in­
creased by bending the stationary
contact blade with a contact
bending tool. If the contacts
are dirty or pitted, they may be
I S
cleaned with a contact burnishing
tool.
Access to the motor control
relay and its contacts is ob­
tained by removing the motor con­
trol relay cover (Fig.
25,
Item
22)
which is held in place over
the motor control relay by two
spring clips.
l f the motor control relay
does not open the motor circuit
to stop the Symphonola motor when
the turntable is at the bottom
of its travel, the motor carry­
over switch (Fig.
25,
Item
2)
should be adjusted.
D .
ALIGl�MENT
OF
REAR
VERTICAL
HELIX
To altgn the solenoid selec­
tor disc (Fig.
40,
Item
9)
with
the rear
Helix
(Fig.
40,
Item
11)
of the Symphonola Chassis, first
loosen the set screws for the
lower coupling arm, allow a stop
pin (Fig.
25,
Item ll) to engcge
the selector disc stop (Flg.
40,
Item
7)
and rotate the helix
until the respective finger is in
position for selecting the cor­
responding record tray. The set
screws of the lower coupling arm
should then be tightened and the
unit is ready for operation.
E . PIN
C
A rf
C
E L RELAY
The pin coincel relay (Fig.
25,
Item
6 )
operates in conjunc­
tion with the selection cancel
switch (Fig.
25,
Item
16;
Fig,
40,
Item
10)
to push do1·m the
selector stop pin when a record
tray is selected.
The selector pin reset
shaft should operate freely s o
that when the pin cancel relay
-