Technical information
o
RADIO
RETAItlNG'S
"Sezuiu
SlNOMBERG
STlOMltlG ro, n.
FedinS, making it
necessary
to oper-
rtc
rolume
control well up
.
. .
Sevcn
hundred
ohm
scctim
of voltage divider
olrcns commonly. Replacc with lG
wttt unit.
STROMBERG-CARLSON
2s,
26. No
reception
Examine chassis bolts.
Frequcntly one
of
these extends too far
end touches
vottage divider.
STROUAERG.CARLSON
25,
26.
Sct sterts
end
!top3
playing
. . .
Look
for
toosc wirc
in
tuning
co,ndcnser
com'
Dartmcnt.
Usuatty
rtill
in
place
but
not
wcll soldered.
Also
check
lfi),fi)O
ohm
fixed relistor
in serier
with
center
lug
of
volumc
control.
Thir sometime3
looJcng
and
shorts to
cround.
STROMBERG
29. On-off
switch
and
tone control
unit is electrically and
mechanically identical to
the'
phono-
graph
and
pickup
switch and volume
control unit. When on-off
switch
con-
tacts arc discovered to be burned
out,
and
thc set
is not
eguipped
with
a
pickup,
interchange
the two units,
mak-
ing
sure that the
"jumpcr"
across the
pickup
input is in
place.
This saves
$1.95
until the customer
wants
to
usc
a
pickup.
STROMBERG.CARLSON
37
Dead .
.
.
test'for
short
in 0.3
mfd.,
400-volt condenser
bypassing
plate-
supply
of
58
i.f. amplifier"tube.
Unit
is section
of by-pass
capacitor
assem-
bly,
part No.
22,702.
15,000-ohm
re-
sistor
will be
noted connected
to de-
fective
component.
Rasping at
room
voiume .
.
.
speaker
cone
off
center and scraping
against
pole
piece. Re-center,
STROMBERG
CARLSON
38
Weak, station
hiss
rvhich
disappears
when the
grid
of
the 58
r.f. tube
is
touched
primary
of
preselector
coil
grounded to
metal
braid
of
an-
tenna
post.
STROMBERC-CARLSON
38, 39, 40, 4l
Weak
reception, loud
station
hiss
.
if
condition
clears up when
a finger- is
placed
on the
grip
cap
of the
58 first
r.f.
suspect
the
preselector
coil for op:n
or sltort
to
rrretal
shieldine.
STROMBERG 48, 49,
50, 5l
Dead,
tubes and voltages check O.K.
.
. defective 500.000 ohnr
{
\\'ait re'
sistor in
the
plate
circttit,r{ thc.i.i
second
detector.
STROMEERG
48, 49
Dial slips
caused
by
the U
rvash-
ers olr tlrtl
friction drive
rtrechanisrrr
binding to tlre
shaft openiug
of
the cab-
irret.
'fo
renterl-r' :
raise front of
<:hassit
slightly anrl
ilrsert thin
rubhel
strilr
between
chassis atrrl
n
oorlctt
clt:tssi.
support.
STROMBER6
CARLSON
60
Oscillation
or distortion
check
grounding
on
shield can of 687.
STROMBER6.CARLSON
I30. I40
Weak .
. .
This
is common on
new
sets.
The sensitivity
control
is on the
back
of
the
chassis.
The
purpose
of
this is
to
limit
local signals,
preventing
overloads
in the r.f. stage.
For in-
creased
sensitivity
turn
the knob clock-
wlse.
STROMBERG
CARLSON
150.
,15s,
160,
t80
Slight
distortion and
decreased vol-
unre
replace 4
nrfd
350
volt
electrolytic
on screen
of
6KZ audio
ampliEer.
It is imperative to use a con-
denser
with the highest
possible
resis-
tance
in
this
circuit since screen
volt-
age is dropped
through a I nreg.
resistor and any
current drawn by the
condenser
drops the screen
voltage.
STROMBERG
CARLSON
I50.
I80
Strong hiss
although
turring indi-
cator functions
properly
replace
6,4'8
with 6J7 with no
other chauges.
STROMEERG
CARLSON
23I
Interrnittent
hum
Tighten
screw
holding filter
condenser
to
chassis.
STROMBERG
635,
636.
"Mushy"
or choked reception
. . .
See if
pilot
light socket
shorts
to
chassis.
STROMBEnG
6'll.
Intermittent reception
or
fading
. .
Often
caused
by
loose lugs on
800 ohm
volume
control.
STROMBERG ilL, 642. Noisy
volume control
.
.
. Replace
rear
unit.
Fading
. . .
Try replacing
the front
volume control unit.
Continual static
. Discard
primary
of
push-pult
trans-
former
and
go
to resistance coupling,
using 25,O00 or 50,000
ohm
plate
resistor
and .01 blocking
condenser. Peculiar
buzz
or
hum
. . .
See
if 25 cycle
trans-
former. has
been installed
(several
New
York
chains sold
sets
of this type) and
if so tighten
transformer laminations
or
replace.
STROMBERG.CARLSON
8{6A
Whistling and
motorboating
. . .
Fre-
quently
caused by
defective l0-ohm
center tapping
variable
rheostat across
filament winding
of
detector tube. Wire
on
this rheostat takes solder so care-
fully
solder
wire
ends
to lugs and
center
lug
t
case
of rheostat.
STROMBERG E{6, El8.
Periodic
fading,
antenna
control fails
to function
properly
. .
.
Check small wire-wound
resictor in series with antenna control. in
rurn
shunted across antenna coil.
Dis-
connect
resistor
and tighten up' rivet
holding one end.
T.
C.
A. CHASSIS
TCA
ClrASStS.
Used
in Tempie
10, Brunswick
10,
Clarion
40,
Bulova
M501,
Columbia
SC3l,
this
chassis has
a tuned 6lter
svs-
tem
with
all inter-connections
inside
a
can.
When
any
section
fuils
the
en-
tire
block
must
be replaced.
Exact
duplicates
are
ditficult to
obtain
so
the
following
is
sometimes
used
as a sub-
stitute:
Connect a
.0005
from
the 47
control
grid
to
chassis,
a .01 from
one
side
of
switch to chassis,
a
12
mike
elec-
trolytic
from
high voltage
end
of
Candohm
resistor
to
chassis.
an 8
mike
electrolytic
from
80
filament
to
center-
tap
of high voltage
winding.
A
tone
condenser
may
be
connected
between
the tone
switch
and
chassis
if desired.
but
in most
instances
this has
been
omitted
by
repairmen
as
it is rarely
used.
Capacity,
.02. Scratchy
sound
similar
to defective
audio
transformer
.
.
Usually found
in
the
Candohm.
Cut
wires inside
unit fof
a coirsiderable
distance
in each
section with
sharp
knife,
then
solder
a.
10,(X)0
ohm, l0
watt resistor
across
the
high
voltage
section and
a 5,0fi)
ohm
l0
watt unit
across
the low voltage
section.
The
original
terminals make
excellent anchor
lugs.
TRAYELER
TRAVELER.
Noise
in models
us-
ing a
yellow
coated,
hoavy
bus
wire
around
an r.f.
coil for
coupling
Re-
move
heavy
bus wire
very
carefully
and
see
if insulation
is not
worn
off, short-
ing
to windings
of coil
underneath.
TRAY.LER
C.
Weak.
.
.
Check
yellow
resistor
under
chassis, mounted
with
a
red
and blue
resistof.
Increases
in
value sufficiently
to
almost
stop reception.
TROY
TROY
515, 5V5, r5
Weal<
.
look for
open .1
mfd
200 volt
conclenser in a.v.c.
circuit.
TRUETONE
TRUETONE
O52
SERIES
(WeUs-
Gardner).
Weakreception...Check
.1 mike
condenser from
35 screen to
ground.
Replace
250,000
ohm, eighth
watt resistor
from 2nd detector
57
plate
to 80
filament
even if
it tests ok.
On
load it sometimes
drops
plate
volts from
180
to
100.
use a one-watt
carbon re-
placement. (1.F.
262 kc.)
61