Technical information

a
I
O
RADIO RETAITING'S
",
"2de
MIDWEST
MTDWIST
t6-t{.
Poor selectivity
and
weak
reception
. .
. This
model
does
not hold
its
align-
ment
due to
shifting
of windings
on
coils.
Coat
all coils with
wax or liquid
cement and
realign
all trimmers.
Go
over all
trimmers
a
number
of times
to uncover
interaction
between
circuits.
Before
realigning
install
a 3
or
4
plate
variable
midget
condenser
in
place
of
the
tone control
assembly. Tone
con-
trol assembly
can be
mounted
on the
side
of the
cabinet. Parallel
this
vari-
able
condenser
to
Cl9, which
is an ad-
justable
coupling
unit
between
oscillator
circuit and mixer grid.
This
condenser
affects
tuning
of
various bands
and by
having
it variable
from
the
outside effi,
ciency
will
be
considerably
increased.
While
aligning
set at 450
kc. have
the
newly
installed
condenser
set at
about
I
mesh
and
screw
C19 to
minimum.
Unstable
operation
.
Ground rnore
thoroughly
all shielded
cables
of
this re-
ceiver.
Double
ground
the three
coil
and
trimmer
frames.
Do not depend
on
rivets.
Realign.
MTDWEST
t6-35
Weak,
accompanied
by
distortion
on
strong
locals.
Dimmer
pilot
light
operates
in reverse
when
using sen-
sitivity
control
on locals
. too much
a.v.c. being
applied
to second i.f.
stag'e. Diagram
shows
a.v.c. for this
Iead
connected to high
side of diode
load
resistor
on
6
F.7.
Disconnect
this
lead
and
connect
to tap
on
diode lotrd
resistor as shown
irt
the diagram by
the
dotted line. This
is
the
same tap
supplying a.v.c.
to the
first i.f.
MONARCTI
MONARCH
I(X)O
Dead
.
.
.
by
observing
the
2525
tube
it
will be noticed
that
one
section
does
not light.
This
is
due
to
a shorted
filter
condenser,
usually
the one
ahead
of
the filter
choke.
Replace
con-
denser
and tube.
MONTGOMERY
WARD
MONTGOMERY.WARD
62-11.
12.
Lach
of scnsitivity may
be cotected by
remozing
the
flter
choke atd 25 mfd.
shunt
condenser entirely
from
thc circuit,
ther
rcmoving
the second dry-electrolytic
flter
condenser and replacing
this tuith
a
4 mfd., 450
volt
type.
MOTOROLA
MOTOROLA
TWIN
8. Excess
vibrator hash
.
. Screw in
bottom of
set
holding
pack
in
place
should first
be
tightened
well. If
this fails
to remedy
noise
put
a
.5
mfd.
automotive
type
con-
denser
on the hot A lead
where
it
fastens
on
terminal lue
and
ground
to case of
set.
MOTOROLA TWIN-E.
DUAL-6.
Buzzing noise frorn
vibrator
pack
audible through signals,
or with volume
control oft .
.
Tighten
self
tapping
screw which holds
the
vibrator
pack
in
its
housing. This is located
on
the bot-
torn
of the
set and
also holds
the
cover
on.
MOTOROLA
8.50
Cuts
.
out
after
set
\\'arnls
un
Check
68,000 ohrrr
rL
rr;rtt
resistrrl in
oscillator
coil can fol
change in
value.
Replace
u'ith
sinrilar unit inside
of
MOTOROLA
8-70
Set
squeals,
cuts out
replace
.01
mfd
condenser
and
100,000
ohm
resistor
in
grid
circuit
of
6VZG. These
two
parts
are
contained
in
one
unit.
MOTOROLA
8-70,
8-80
Loud
hum
rvl-rich
increases
as vol-
unre is
decreased.
Drill
out
rivets
holding pushpull
input
transfornrer
and rotate
transforrtrer
to
find
posi-
tion
of rrrinirrrurl
hunr.
Fasten
in
place
u'ith
brackets.
MOTOROLA
IOY.
I2Y
Cuts otrt
.
replace
2700
ohm bake-
lite
cased
resistor.
MTDWEST
t6,
35
I)istortiort
rrlrcrr
voluntc
cotrtrol is
turtted
urorc
tharr
I
on lo<rk
for.
brokeu
lead
on
.l
corrrlenser
counectecl
frorrr
Jrlatc
of
lirst
:rrrrlirr
trrlrc
(76)
ltt
torrc
cotttrol.
MOTOROTA
3,r
Noisy
tighten
i.f. coil
shidds.
These
are
fastened
to
the chassis
with
self tapping screws.
MOTOROTA'35-'36
-
Jumps
_
station
on bumpy
road
.
loose
drive
gear.
Taki-out
chassis
reset
drive
gear
and
tighten.
MOTOROLA
44.
Power
supply
unit
hums
but
set
does not
play
. .
. Take
vibrator
unit
apart. Find
2
small. flat
condensers
on
top of reed
unit.
The
reeds
may
be identified
from
the
outside
by
tracing red
and
green
rubber
covered
wires.
Remove
original
condensers.
Solder
a .01,
1600
volt
d.c.
tubular
unit
externally
to
each lead,
joint
the
two to-
gether
and
ground
the midpoint.
MOTOROLA
50
High
background
at
low
frequency
end
. .
. shorted
antenna
scries piddei.
Metallic
shavings
between
segments
cut,
tlrrough
nrica.
MOTOROLA
s0, 60,
80
lrtterrnittcrrt
opcratiorr
itrspect
tlre grourr<l
rctrtnt
lea(l
irrsitlc
tlrc vibr:r-
tot' for
lo,rsg 1;1' lrlokt'n
corrncctiorr..
MOTOROLA
55.
Vibrator
hash
and
mechanical rattle
.
. . Remove
pow-
erpack can
enclosing vibrator
and
power
transformer,
turn
over and
mount
se-
curely on chassis
with
self-threading
screws,
Replace vibrator
and cover
and
reverse
"A"
leads
to correspond
with car
battery
polarity.
Discard
tin
cover
but
place
rubber
bands around pack
before
ptrtting
chassis back
in case.
MOTOROLA
55.
Elkonode
unit
is
short-lived
.
Connect
50.000
ohnr re-
sistor
across
output
of
replacernent
unit.
MOTOROTA
60
Volu,nre
cutting
in
and
out
.
, . speak-
er
6eld
wires
loose.
These
joints
ap
pear
to be
welded
instead
of
soldered.
MOTOROLA
60
lntermittent
fading
inspect
nrica
in
antenna
and r.f.
trinrmers.
MOTOROLA
64, 94
When installing
new
dial
pointer
lights,
turn
base
of socket
so that
pointer
light fornrs
sharp
line
on dial,
otherwise light
rvill
be
r,vide
and
ragged.
MOTOROLA
65
Distortion
after
warming
up
.
. .
change
in value
of
bleedei
resistors.
Replace
22,000
ohm plate
and
screen
dropping
resistors.
Also,
300
and 1,500
ohm
resistors
in
cathode
of 75.
MOTOROLA
65
l\{otor
rtoisc.
espcci;rll_r' orr
l,'or.tl \:ti
.
. .
Slriel,l lr,,t
".\"
lc:rrl
r.,,rrrrcctirrg
set
l(,
[rr.e
hl,'r'li
uith
rl,rulrle
l;r)ci
of
cr)l)l)cr
bntirl.
(
irorlrtl
lrr.;ri<l
;rt sct
ettr[ otrly.
MOTOROLA
65. 70
GOLDEN
VOICE
Dead
. .
. Check
dual
.0008
condenser
located
near
bottom
oI
OZ4
Tubes.
MOTOi,OLA
75
Intermittent
.
.01
coupling
con-
denser (marked
l5l8)
between 25
plate
and 4l
grid
shorting,
replace.
MOTOROLA
75
Vibrator
failure,
especially
on
sets
mounted
upside
down
over
the
steering-
column
.
.
check
the
rubber
covered
leads
in
the
vibrator
where
they
are
tied
with
cord
at
one
end of
the
vibrator
frame.
Very
often
these leads
break
from
the
constant
movement
of
the
vibrator
franre.
Replace
leads
with
flex-
ible
wire-
MOTOROLA
77
Vibrator
hash
.
Cut a
piece
oi
tin
to
fit top
of
power
pack.
Fasten
this
by
the two
screws
which
hold
the
power
transformer
in
place.
If
any hash
still
persists
solder
a
flexible
lead
to the
top
side
of the
first
r.f.
section
frame
of
the
gang
condenser
and bond
to
chassis.
37