Technical information
O
RADIO
RETAITING'S
"Sq>uie
G.E. F63
Distortion
on strong signals.
Resistor
(R3
in
diagram)
conducted to
wrong
'lug
on terminal strip.
G.E
F63
Anterrna coil burnecl out . . . .
defec-
tive rvale
bancl
srvitch
rvl'rich
goes
be-
yond
stop
positior.r
ancl
places
98 volts
on the
rvinding.
GE
F
63, 55, 65
A
squeal
rising
in
pitch
as
volun.re
control is
advanced
often results
rvhen
primary
leads are reversed on a
re-
placement
transformer.
G.E.
F63, 65, 66
Pointer does
not
r-nove
when
dial
knob is turned.
Not
enough fric-
tion
ir-r drive
assembly.
Insert small
fibre or
cardboard
strips between
pres-
sure
plates.
6-E F63, F70
Due to
the
itrverse
feedback usecl
irr
thesc sets a stlueal will sonretinres cle-
lekrp u'hen the output
transfornrer
is
replacerl.
This nray be
correcterl bv
r-evelsitte
corrrrections
to the trans-
fo rtrre
r.
GENERAL
ELECTRIC
A6+, 166, A67.
Severe
a.c.
hum . . Accidental
con-
tact between
high
voltage
a.c.
terminal
of
the
SZ4
tube socket
and the
elec-
trostatic
shield
of
the cartridge
by-pass
condenser
C23
causes
a
hum unlike
poor
6ltering.
G.
E.
K-64
Motorboating
and cutting out .
re-
place
600
ohm first r.f.
bias
resistor.
Oscillation . .
. Check
double 4 mfd
electrolytic.
GE
A65
Hum
and distortion
insert
50,000
'ohm
resistor in
series with
6C5
plate
resistor at
the
B
plus
end.
Bypass
junction
of
these
resistors with
.1
mfd. or
larger
600 volt conclenser.
Distortion
is sometimes caused
by
de-
fecti'r'e 50,000
ohm
plate
load resistor.
G.E.
A65
Weak
or dead,
2,000 ohm
plate
dropping
resistor burned re-
place
.05
mfd bypass
in
grid
circuit
ot 6K7
i.f.
GE G65
Oscillation and distortion
. .
. .012
mfd
condenser from
plate
of 6K6G too
close to
yellorv
automatic
tuning lead
causing feedback
to control
grid
of
6\8G.
24
G.E.
M65
Oscillation
when
volume control
turned on
full .
.
. Check
all filter con-
densers.
Replace 8 mfd
section
with
red leads with
new unit.
GE
466
Static but no
reception . .
.
oscillator
not operating.
If
new
6,{8
tube
does
not restore
action,
replace .05
mfd
con-
denser bypassing the
40,000 ohm
grid
re-
qistor,
GENER,AL
ELECTRIC
A57.
Noise, resembling
interference
gradu-
ally becoming
distortion
. . Defective
500,000
ohm,
6F6
grid
resistor.
Some-
times
hard
to
locate
as it
measures
cor-
rect
value when
set is turned
ofi,
G.
E. A-67
Poor
tone and
distortion
change output
grid
resistor
from
500,000
to
150.000
ohms.
G.E.
A67
Dead.
test condenser
shunting
candohm
resistor
for short.
G.
E. E7I
Dead
check second
i.f.
plate
bypass condenser
(.02
mfd) for short.
Also check
2200
ohm
plate
dropping
resistor by
removing second i.f.
coil
shield.
No volume .
replace 2200 ohm
second i.f.
cathode
resistor.
GE F74
Intermittent
low
frequency
motor-
boating
tighten
all
i.f.
cans.
6E A75
Fade-out after
15 minute warmup
. Check
.01
mfd
condenser
in avc
lead of
i.f.
G.E. F75
Noisy when tapped. Louvre
dial
not
properly grounded.
Suspect
cop-
per
ribbons at
points
where
they
are
spot welded to chassis.
G. E. 76
Dead
on broadcast
band . . . shorted
.01 mfd 200
volt condenser
connected
to
shaft
of all-wave switch
by
green
wire. Replace with
600 volt condenser.
GE J8O.R,CA
R8
Crackling
and
weak
reception
.
.
.
first
audio
primary.
There
are two trans-
formers
sealed in
can, no
room
to mouni
another.
Change
to resistance
coupling.
Substitute 100,0(X)
ohms for
primary
an-l
300,000 for
secondarn
couple
det.
plate
to
audio
grid
through 0.5 condenser.
GE KS0X,
K80,
KEs.
Failure to
operate at
high-frcquency
end of
"C"
bands,
or even
failure
to oper-
ate over
these
bands
at all
. ' ' TrY
several new
2A7's
in oscillator
socket.
Oscillation
howl
on
strong
signals
Enclose
grid
lead of
287 second
de-
tector
inside
cylindrical tube
sh,eld.
G.E. E8I
Distortion,
.low
volume
after
l0
min-
utes
of
operation,
plate
voltage
on
6L6
drops to about 25 volts
6L6
shorted
internally
to
shield.
Replace
with similar
tube
or 6L6G.
G.E.
E8l, E86
Loud
background hoise . .
. Change
cathode
resistor
of. 6K7 first i.f. to
25000
ohms.
G-E E8I. E9I
High noise
Ic'vel betrveen sta.tior.rs
ttray be recluced by inserting
a 5000
ohni half watt resistor bvoassetl
rvith
.{).i 11,54 cottrlettscr irr
the- cltthorlc oI
the first tletector
an<l last
i.f.
staee.
GE M-81, RCA
l,l3
For a
gradual
loss of
pep
and volume
on this set be suspicious
of the
grid
resistor
and
filter network
on the 56
tube amplifier stage.
Changing
of the
condenser will
work
wonders in some
cases,
(There
are two models of
this
set-information applies to
model
with
divided
or two
resistor
grid
network.)
G-E A 82
In
this receiver
extremely noisy
operation
over the broadcast range
and
interr-nittent
operation
over
the
short
wave
ranges n-ray
be caused by an
open
by-pass condenser from
the
R.F.
cir-
cuit
primaries
to
ground.
It
is neces-
sary
to remove
the entire
"sentry
box''
assernbly in
order to reach the
con-
denser. Sometimes it is necessary
to
increase
the
value
of this
particular
condenser
to
as much as 0.5 mfd. be-
fore
the
noisy
condition can be com-
pletely
eliminated.
G.
E. A-82, A-87
Weak
.
.
.
The 6xed
padder
(C-46)
across the
sccondary
of
the second i.f.
traosformer should
be 65 mnrf.
[n
a few instances this condenser has
changed
value
sufficiently to throw this
stage out
of
alignment. The trimmer
(C-45)
will not
peak.
and
all signals
will
be
weak. Replace-C-46
with an-
other 65 mmf. capacitor.
GE
J83.
Fading . . .
Replace 50,000-
ohm resistor under r.f. coil
with
a 60.000-
ohm
unit and
resolder
all oscillator
coil
connections.