Service
Manual '41 Models 7800, 7850, 8800 and 9800
accessible.
It should
be
cleaned
with fine
sand
paper
Olld
wiped
with a clean cloth.
C .
ST1IBTING WINDING CUTS IN AND
OUT CONTINUOUSLY
Thls ls usually due to bind
ing in the chassis
m
ec
ha
ni
s
m
which
allows
the
motor to just
corne
up
t
o
enough speed to open the
start
ing winding switch, whereupon
the
motor
speed is imlnediately
re�
duced due to the
h
ea
-vy
d
ra
g
,
and.
the starting
switch closes
again,
D.
MOTOR
FUSE BLOWS
If the motor fuse
is blown
it
should
be
replaced with
a
2 . 5
ampere non-ta:nperable fuse
(No.
14173) .
Before
r
e
p
l
a
c
in
g, find
what
caused
the
:fuse
to
b
l
o
w
.
·
T
h
e
re
are a
number of
reasons
that rnay cause
the
motor fuse
to
blow.
The most usual
reason.
is
the failure to
remove
all
ship
ping
bl
oc
k
s.
Be
sure the in
strument is completely
unblocked.
Binding in the
transmission
4,
No.
3054)
and
and tight bearings in
t
h
e
motor may
cause the
motor
to
overload.
After loosening
the
c
ou
p
l
ing
(
F
ig
.
41
No.
1080)
the
motor
should turn
freely.
Record trays
may
be
jarnrned
due
to dirt or grit in the
tray
gt'ooves.
N
e
i
th
e
r
vase line nor
grease should ever be used to
lubricate the
tray grooves
b
e
cause
the trays are almost cer
t
ai
n
to bind.
If
grease has been
used
i
n
the
tray grooves, it can
be cleaned off by applying a
light
grade of
good quality
lu
bricating
oil with a brush.
If
the instrument has been
in a
cold place over
n
i
g
h
t
, it
should be
allowed to
warm up be
fore operating,
otherwise
the
lubrication will be stiff,
plac
i
ng a
heavy
load on
the
motor
which will often blow
the
fuse.
3 .
RECORD TRAY SELECTOR P U t l l !f G !JUT
TWO
OR MORE T R A Y S AT O H E
T I M E
The
sele
c
t
o
r
helix rollers
(Fig. 6A,
No. i22c)
should b
e
in
line
with
the centers of
t
h
e
selector
pawl
springs (No. 1184).
I
f
out of line so that the roller
also engages
the
spring above
or
belo1� the one
selected, it
may
depress two
pawl springs
causing
two
lrays
to be withdrawn.
The
selector slide
rail
(
Fi
g
.
SA,
No.
1181)
may have moved down-
ward slightly, o
r the
h
e
l
ix
(Fig. 6A,
No. 6178)
m
a
y
have
moved up or down.
Before at
tempting to re-align the
selector
slide
rail,
be sure
that this
1s
necessary.
Make certain that
the
selector slide pawls
(
Fig.
SA,
No.
1185)
are
kept in alig!llllent
with the grooves
in wntch
the
lugs of
the trays move.
Q .
T I M I H G U F M E C H A N I CAL
SELECTOR WITH REAR H E L I X
In
re-aligning
the helix., be
sure
that
the proper
mesh of
the
ro1ter gears
(
F
ig
.
SF,
No.
1210)
is
20
maintained,
so
that the timing
of
the selector is not disturbed.
Tf
o
n
e
or two
rollers are out of
Summary of Contents for 7800
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Page 44: ...CrSSI S REAR I I Ell CUTAWAY f3 I ll 37 ...
Page 47: ... I iit L 7 8 _ 1 I I I I F I G U R E HO 6 SYM HONf ...
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