Technical information

."
RADIO
RETAILING'S
,,.
eh'ui@
G.E.
Er55,
rl26
Noisy
volurne
control.
Before
replacing
volume
control,
replac-e
6C5
firit
A.Ir.
In models
E86,
E95'
and
E,105
trv
replacing
6F5
first
A.F.
GE
I937
MODELS
Pilot
light
burnouts
insert
150
ollnr
r€sistor
in
centertap
of
high
volt-
age
winding,
also
l5 olrru
resistor
irt
ser-ies
with colorattra
liglrts.
Tlris
offsets
hieh
line
voltage.
G.E.
I93.7
MODELS
Colorama
lights burn
out
insert
a
150 ohm
reiistor
in the
centertap
of
the
high
voltage
winding.
Also,
a
15
ohm
resistor
in
series
with the
lamps
will
increase
their
life.
GE I?37
AUTO
RADIOS
Periodic distortion
at
low
volume . .
.
check
for trouble
in
power
tube socket
as
wax
from r.f.
.l mfd
bypass
runs
in
tube
prongs, Erratic
operation
in these
sets
is often
due
to a
defective
discrim-
inator-transformer
winding.
G,E.
COLOR
TUNING
Due
to the
series
wiring
of
the
three
green bulbs,
one
defective
bulb
will
iause
the system
to
be
inoperative.
When
replacing
bulbs make
sure
the
new bulb
is of
the same
current
rat-
ing.
If the
green lights
are
on
con-
stantly
the trouble
can
usually
be
traced
to a defective
rectifier.
GENERAL ELECTRIC
(RADIO-FORTE)
If tuning
rnotor seenrs
to
lose
pol\'er'
look for
weak 60
mfd.
electrolytic
across
notor
winding.
GENERAL
MOTORS
GM.
Ll/here
tone
qu4lit!
o!
,nodcls
usino
hoizontal
tuning
dittls
k
bd
al-
thoigh
plote
polentiols
ot
fuml
45's-checks
O.K.
d;
not
-condarm
tlrr
p:rsh'pull
trans'
lormcr.
Looh
for
a dcfcctive
tonc cottrol
ztariabla
resistor.
Rcplacc
it toith
a 500pAO
ohm unit,
GEI.{ERAL
MOTORS
IIO
I\Iushy tone.
.
. .
Replace
250,000
ohnt
.tetector
load resistor.
GENERAL
MOTORS
251
To
prevent
cross
ntodulation ol1
strong
signals
install
a shielded
lead
from
the
antel'tna
post
to anenna
coil.
.\lso srvitch the
lead frorn the
antenna
coil to
the
lug llext
to the
coil,
using
the
forn-rer
lug to conttect
to
the oscilla-
tor conclettser.
GM
120, l3u,
140. Intermrttent
drop
in
volume
but
set does
not
go
dead
. . .
Tighten screws
holding stator
plates
on
gang
condenser.
Both top
and bottonl
icrews
should
be tightened'
Or,
solder
wire
lead between
top
and
bottom
lugs'
Same
trouble
common
in
'other
sets,
such as U.
S. Radio
27,
where
grid
lead
is connected
to
one side
of stator
platcs
and
coil
is connected
to
opposite side.
26
GENERAL
MOTORS
I20,
I30,
IIO.
Weak
reception
or
dead set
in serial
numbers
below
291004
or
17fl)B,
all
voltages, condensers
and resistors
ap-
parently
ok .
StraP
a 200
ohm,
10
watt resistor across
the
2z[0 ohm
sec-
tion of
the voltage
divider
used
for
bias
to
decrease
control
grid voltage
of
tubes
and
snap
up
sensitivity.
GENERAL
MOTORS
60I574
1'rrbcs
light
lrut vibr:ttor
is de:t<l .
. ' .
rel)rove
prlrr'cr trans[orltter
frottl catt.
'l'his
rvill
<lisclose
an
oblortg
cotrdenser,
lritrt
rruurber
R11549DX,
cotttrected
to
ihc
"A"
lirtc
chol<e.
Repl;rce
this
unit.
GENERAL
MOTORS_LITTLE
GENERAL
Intermittent
oscillation
or fading.
.
.
.
Check
all
resistors
and
condensers,
ground variable
condenser
rotor.
GOODYEAR
WINGS
COODYEAR.WINGS
Distortion,
dead
deiective
tone
control
on
lid of
set. Set
returns
to
normal
when
lid is
removed.
Replace
control
and condenser
connected
to
it.
GREEN
FLYER
GREEN
FLYER
PHONO
MOTO
(6
volrl
Uneven
speed,
especiallY
in cold
weather
. .
. .
wash
out
all
grease
with
gasoline and
lubricate
with
light
oil.
Rearrange
field
coils
as
illustrated
in
the
accompanying
diagram.
This in-
creases
the
field
current
giving
greater
Dower.
Crossover
connection
of fields
must be
used so
that
fields do
not
buck
each other.
GRUNOW
GRUNOW.
Ca1>acit-v of
coutlensers
ruarketl onll'
s'ith
part
uurrtbcr:
GRUNOW
.tB
Distortion
which
shows
uP
after
5
to
l0 minutes
of oPeration
rePlace
.02
mf d. couPling
condenser
Part
#29567.
GRUNOW
5E
Motorboating,
intermittent
.
Re-
place
gart
No.
28726,
a .l
mfd
400
v.
plate
filtering
condenser.
gRUNOW
6C.
60
Distortion
.
.
a.f.
couPling
con-
denser
leaky.
As
a
matter
of
routine
it
is advisable
to
replace
this
condenser
regardless
of
comPlaint.
GRUNOW
6C
I-ortrl
ltutrt
stl'sl)('ct
()l)tll
coll-
rletrscr
cottttcctctl
lretwcelt
jrtrrctitlrt
of trvo
2.i0,(Xn
ttltttl
resistors
irr tltt'
gri<l
of
the
'12
:rtrtl
groutrrl.
Rt'plltcc
with
.07.5
nrfrl unit.
GRUNOW
60
Hunr
Late
trtodels used
12
mike condensers
across the
60(X)-ohm
bias
resistor
connected to
75 cathode.
In
early
models this
was omitted
and
hum developed
later. Install
low
volt-
age
12 to 20 electrolytic.
Voltage
is
oily
2 or three
volts
across
the bypassed
resistor.
GRUNOW
6D
Motorboa,ting
when
volume
control
is
turned
to
reduce
volume
rePlace
1 mfd
condenser
connected to
low
end
of
volurne
control
(end
with
black
un-
shielded
wire) and
ground.
GRUNOW
6D.
Intermittently
refuses
to start once it
is turned
off .
. .
Replace 75.
GRUNOW
7-A.
Volume droPs
in-
terrnittently
but
set
does
not
go
com-
oletetv
dead
.
. . Check
two
.l
mike
.onde-nsers
connected
between
lower end
of
r.f.
coils
and
ground.
Located
in
small
can
fastened
to bottom
of
coil
shields.
Lugs on
the
can
are blanks.
Connections
made
by wire
leads
inside'
shield.
GRUNOW
74.
Interrnittent
or
no
reception
Common
cause
is
de-
fe' le
.l condenser
in block
back oI
t",!irtg
gang, identi6ed
by
green
lead
which,
with two
red
leads, is
connected
to a common
terminal
at the
left
rear
of
the
shortwave
switch.
Use
a
600-volt
replacement.
Also
replace
1,000-ohm
resistor
located
nearest
6lter condensers
on resistor
bank,
as this
is usually
ruined
by
failure of
the
condenser
described
above.
GRUNOW
7A.
.
Motorboating
and
blocking
Due to
two
large square
coil
shield cans
mounted together
under
condenser
gang
working
loose. Ground
with
heavy wire
from
each carr to
chassis.
NUllttsEtl
2E7
t7
2E7 t9
2E720
28721
26722
267 2t
267 26
26729
28876
29tt5
29n0
2915t
29561
29567
29562
29E12
29Ett
296rE
29990
,0t41
c.{P.{cI'l't
.
002
. 00,1
. 005
.01
'04
.05
.l
.5
.02
.l
.0t7
.01
.075
.o2
. t5
.0,1
.004
.001
.02.
.05
VOLT.{GI.
700
700
700
500
400
400
400
t00
500
t00
500
400
t00
400
200
500
700
700
100
t0n