Seeburg 7800, Service Manual

Page: 20 / 87

Service Manual '41 Models 7800, 78!30, 8800 and
9800
B .
PICKUP
Two of pi
c
kups
(F-3121
and are used inter­
changeably i:n the tone arm
(Fig.
8 ) .
When the pickup becomes de­
fective, it is recommended that
the entire uni t be returned for
a factory rebuilt pickup
.
The pickup unit is a scien­
tific device. Its characteris-
tics are determined
by
its cor.­
struction and the materials
used. To dismantle the unit will
reduce its magnetism, change the
damping a:nd introduce maladjust­
ments which cannot be corrected.
Such a unit will be of question­
able
q ua l ity and infer i.Ol' to a
factory rebuilt pickup which can
be obtained on exchange for a
nominal charge.
3 . SOUKO
E QU I PM E N T
A . AMPLIFIER
The amplifiers used in all
of the
1941
model Syniphonolas are
designed to operate at any volume
set by the control from very low
to full output without distortion
or bad tone Quality. .All the
amplifiers are eQuipped with dual
tone compensators; one compensa­
tor
(Fig.
10.r Item 19; lo,
Item
19;
F
ig.
16,
I tem
i s
used
for modifying the high fre­
quency or treble notes and the
other {Fig. 10, Item
21;
Fig.
13,
Item
21;
Fig.
16,
Item
.21)
is
used for modifying the lower fre­
quencies or bass notes. Care
should be used in adjusting these
b
ec
au
s
e bY
subduing either the
high notes or the low notes to
too great
an
extent, the tone
quality and faithful reproduction
of music will be greatly
im­
p aired.
B. VOLUME CONTROL
If"
the volume control (Fig.
11,
Item Fig.
14,
Item
3 ;
Fig.
17,
Item
which i s located on
the back of che amplifier panel,
should cause the volume to
jump
to a high level when turned
slightly and then go down again
I
:2
when turned slightly farther, the
control i s defective
ar.d
should
be replaced.
C . TUBES
When installing or replac­
ing tubes, special attention
mus t be pai d to the designated
nuruber on each tube. The number
on the tube must correspond to
the number on the t:u'be socket.
Each tube must be inserted in
its proper tube socket; failure
to do so may result in damage to
the tub e. �.1ake certain that
each tube i s firmly pushed into
its socket to make proper con­
tact.
D
•
SPEAKERS
The speakers
(
F
ig.
1 ,
Itero
Fig. 2 , Item
4;
Fig.
3 1 Item
used in each model Symphonola
are desigDed and matched to op­
erate with the other components
which make up the sound equipment
for that particular instrument
and are built to withstand the
full volume of the ampl1f ier
without
injury.
Care
should
be
taken not to allow dirt to enter
the speakers a s this may cause a
rattle or bad re p rod u cti
o
n of
music,