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11-2
RADIO
RADIO AND OTHER ACCESSORIES
(3
98)
trol knob
; however, the
rod exte nsions must be
pulled out manually.
The antenna is hinged so that it will not
ordinarily be
damaged
when coming in contact
with
low
hanging limbs or other
obstructions.
The
hinge allows
the antenna
to yield forward
or backward,
and
the antenna
r
eturns
to its
normal position automatically as soon as
the
obstruction is
passed. When
ente r ing a garage
with a
low
hanging
overhead
door,
however,
the antenna
should
be turned
to "down" posi-
tion to avoid the possibility of
damage when
the
car is
backed
out of garage.
c.
Swit ch,
Volume, and Tone
Control
O
peration
The first portion of rotation of the switch
and volume control knob
operates
the switch to
turn on the radio; further rotation increases
the volume. This is the
left
knob on S
eries
40
and
1949
S
eri es
50-70.
It
is the right knob on
1948
S
eries
50-70.
Rotation of tone control to extreme
"treble"
position gives brilliant reproduction of the full
tone range. This position will reproduce speech
very clearly
and
distinctly.
Rotation counter-
clockwise
toward "bass"
diminishes brilliance
and ac
centuates
low notes.
d. M
a nual
Tuning Operation
Wh
en
tuning
manually,
or wh
en setting
up a
station
on
one
of
the
push
buttons, remember:
"A good r
adio properly tuned
will
give
the ut-
most
in radio r
eception,
while
the same
radio
improperly tuned may be
quite unsatisfactory.
"
If
the program sounds
screechy or
distorted,
it
is probabl y
caused
by
imp r oper tuning and
ca
n
be
cor recte d
by
adj ust ing
the
tuning kn
ob
sl
ightly.
Since the
low notes a
re
mor e affec
te d
by tuning than the high ones,
it
is
a
good
plan
t
o t
une
t
he
set
to a
point
wh
ere the low notes
a
re
hea r d best a
nd high
not es are
clea r but not
screechy. Turning
the
control knob back and
for th
until
the
st at ion is almost
lost
on eit he r
side
will enab le
the
operator to
hea r the
diff
er-
ence in r
ecep ti on and
select an inte r med ia te
position g
iving
best
results.
e. Push Button Operation
To
operate
th
e
push buttons, simply push
the
buttons in as far as
possible.
The button travels
very
easily
for
a ways
and then a
slightly
harder
push is
necessary
to
complet e the travel.
It
is
suggested
that the operator try tuning with the
buttons
a
few times while the car is standing
still
so that he can watch the
pointer
mov
e
ac
ross
the
dial,
and thus get to know
the "push"
necessary to operate the tuning
mechanism.
11-2 RADIO
TROUBLE DIAGNOSIS
The trouble diagnosis information in this
paragraph is of a non-technical
nature.
It
is in-
tended as an aid in locating minor faults which
can be corrected without a specialized knowl-
edge of radio and without sp
ecial
radio t
est
equipment . If the suggest ions gi
ven here
do not
affect a correction, further testing should
be
done only by a
trained radio
te
chnician
hav
ing
proper
test
equipme n t .
a.
Troubl e Caused
by the Antenna
An
antenna can cause a radio to
be
weak,
dead, noisy or intermittent.
Before
doing any
work on the antenna installation always
check
the trimmer adjustment as described in para-
graph 11-3.
The easiest method of checking an
antenna
installation is to substitute a piece of wire about
10 feet long in place of antenna, at end of a
standard antenna
lead-in,
and
place
outside and
away from the car. If radio op
erates near
nor-
mal with substitute antenna, some part of car
antenna or lead-in is at fault.
Lead-in wire may be
checked
for "grounds"
by
removing lead-in cable connector
from radio
receiver and checking with an ohmmet er
from
connector tip to car bod
y.
This check should
show an ent ire ly
"open"
circuit. CAUT ION: Do
not check w
ith
a lamp or any
device drawing
current, since th
e
conductor inside
loom is only
.010" in
diam eter
and
will burn
off
easily if
g
rounded.
The
most common points to
be
chec ked
for
"grounds"
are
at attaching
scr ews fo
r wind-
shield di
vision inner
molding and
escutcheons
at
upper
and lower ends of
division inner mold-
ing. Grounds will occur at
screws
if
lead-in
wire is
improperly installed
and
allowed
to
pass
directly ben eath one
or
mor e screws. The lea d-
in
wire
also
may be pinched bet ween
gar nish
molding a
nd t
he
escutcheo ns .
To
chec k antenna for
ca
use
of nois y
or
inter-
mittent
ope rat ion, fully ext end ant en na and
turn radio volume cont r ol on full.
If
no
ise
ap-
pears
in
speaker
check
antenna
and lead-in wire
for
loose connections.
If
wiggling lead-in
does
not cause
noise,
rap antenna rod with
insulated
end of screwdriver: if noise then
appears,
check
antenna
for shorting to car body or corrosion
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