Seeburg 7800, Service Manual

Page: 16 / 87

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Service Manual '41 Models 7800, 7850.
SSOO
and 9800
tacts of the series relay close.
The series relay thus energizes
the cancel solenoid permitting a
credit to be cancelled from the
ratchet wheel.
F.
IN'XERLOCKnm CIRCUIT
When a selector button is
pressed, the interlocking cir­
cuit (Fig.
19)
is closed. through
one of the switch s eglllent s of
the selector switch. ''fter the
cancel solenoid has travelled
t�rough the major portion of its
stroke, it closes the contacts
of the interlocking switch (Fig.
19,
Item M6) the inter­
locking relay
19,
Item 147),
which opens the sertes relay cir­
cu
t
t and locks itself uP by means
of maintaining contacts.
CL
IN
TERLOCKI.NG
RE1AY
After the interlocking
switch operates, operating the
interlocking relay, the normally
open or mainta1ni.ng contacts
close and maintain tbe circuit
through the interlocking relay
even though the interlocking
switch contacts open.
When the normally closed
contacts operate they break the
circuit through the series relay
(Fig.
19,
Item Ml). The series
relay then drops out, the credit
canceling solenoid is de­
energized;
and
the interiocking
switch opens. As long as the
selector button is held down, the
interlocking relay will be ener­
gized and the starting relay
and
the ca.ncel solenoid will be in
their normal position ready for
a.�other selection to be made.
However, before another selection
can be made, the interlocking
relay must first return to its.
normal position allowing the
7
series relay circuit to close.
This means that the operator can­
not make another selection until
he first removes his fingex·s
from the selector button.
H. NON-CHEATING CIBCUIT
In order to prevent cheating
b y tapping the selector buttons
lightly, a non-cheating circuit
is included in the electrical
selector. This circuit increases
Uie Period of time during which
the series relay is energized.
The circuit is in series with the
30
obm
Candohm
res.tstor (Fig. 19,
Item
J'i\8).
When the push button
begins to travel backward, the
interlocking circuit is broken
some time after the series relay
circuit is broken. If the
series circuit is completed
momentarily, energizing the
series relay, the left hand con­
tacts on the series relay will
close and permit current to
travel through tbe series relay
by way of the non-cheating cir­
cui t until the .interlocking cir­
cuit is broken at the selector
switch. This current puls.e is
sufficient to operate the series
relay long enough to cause a can­
cellation of credit, To further
insure functioning of the non­
cheating circuit when the push
button selector switch is
ulated, contact gap A (Fig.
has been included. It closes on
the initial motion of the cancel
solenoid plunger a.nd connects
series relay small contacts
directly to the energy source.
I. ELECTRICAL CO\JNTER
To maintain proper opera­
tion of the electrical counter
(Fig. 26, Item
7)
on cancella­
tion of the last credit, a cir­
cuit consisti�g of a resistor