Technical information

O
RADIO RETAILING'5
"Squire
CROSLEY 58
Dead.
.
Suspect
metal
cased con-
denser containing
r.f.
plate,
screen
and
cathode bypass
(part
#W7753).
It
frequently shorts out, sorrretimes burn-
ing
one or both of the
Candohm
re-
sistors at
the back
of
chassis. As a
safety
first
measure solder
the
speaker
plug
to its socket connections under'
chassis.
This is
a
constant source
of
noise and
intermittant reception
as
plug
often
works loose.
CROSLEY 72AF
Oscillator will not track . re-
place
mica
condenser connected across
oscillator
trimtner.
Condenser
open or
making
poor
contact.
CROSLEY
77,
84,
AMRAD
84. Fading
in and
out
'Ihe
renredy
is
of
terr
simply
replacenreut
of .l mfd. con-
densers coulrlirrg r.f.
coil sections to
ground.
It is rarel_r'
nece:ary
to replace
rrrore
than
one.
CROSLEY
95
Poor
quality, rveak
Check
po-
laritl' of
speaker
field
leads'
CROSLEY ROAMIO 98
Dearl
look f
or clcf
ective tone
control.
Replace
rvitlr new
control.
CROSLEY
I02
Internritttlrt
br.oken or
loose
lcad
fronr
r.f. fran5forntcr
to
i{ang
contlenscr.
Condenser
is nrouuted
on
rubber
and
is
perrnitted
sonle nr()venrer-rt
breakinq
the
lratl.
Replace
lead
but leave
long
enough
to
pe.rr-lrit
condenser
nrovelnert.
CROSLEY I20
No
reception,
crackling shunt
2000
ohm
resistor
across
divider section
supplfing oscillator
plate.
CROSLEY I2O
No reception,
background
noises
but
not signals.
. . . Shunt
2000
ohm resistor
across
divider
section supplying
oscilla-
tor
olate.
cRosLEY 122.
Type
24
oscillator
fails
to oscillate
at low
frequency
end
of
dial and new 24A
won't work at all in
this dynatron
circuit . . .
Shunt
a l-watt,
750-ohm resistor
across
650-ohm volume
control
and 24A
will
go
to work.
CROSLEY f24. Breaks into
oscilla-
tion when light is
snapped on or ofi
anywhere
in
house
.
. Move wircs
leading from a,f.
transformer to
grids
of
,
47
kom between
socket terminals of
27
dctector and 5l i.f. screen terminal and'
tic
them near the detector choke.
CROSLEY
I24
Intermittt.nt partially
slrorted
tuning condenser.
A
dead set rvhich
oscillates
when
firrger
is
placed
on 35
first i.f.
tube
indicates
a defective
2.:l first
detector tube.
CROSLEY I24
Oscillation, sounds like loose voice-
coil,
small capacity from 47
grid
to
47
grid
clears it
up Caused
by
inductive
pickup
by leads
of
47
tubc
grids
from
audio
transformer iecondary.
Remove leads from
present position
between
detector
and
i.f. sockets and
fasten with stiing
or
tape
to mica
con-
denser on side of chassis.
CROSLEY
124. Fading.
l.ook for cold-
soldered
joint
on i.f.
transformer
lug.
cRosLEY
124-1.
Fading,
signal
returns to nornral
volume if
set is
switched
off then
on again,
or
if
tube
is
pulled
out and
then
re-inserted
Replace
condenser
block W22412 which
contains
four
.l condensers.
CROSLEY 124-1. Iiading
and inter-
m;ttent reception
.
Generally due
to
high leakage
in one
of the four
.1 con-
rlensers located
in condenser.block
No.
W22412.
Also check
the two .25 nrfd.
units
and
the
.5
mike in block
No.
W23736
for high
leakase.
rIF
175 kc.)
CROSLEY I25
No
plate
voltage
or-r oscillator detector.
Check i.f. trimmer'condensers.
Inspect
the
mica
separators for
possible
short.
CROSLEY
127.
Sudden
drop
in
volume
accompanied by
failure of
the
tuning
meter. Partial short
in
the
i.f.
transformers.
CROSLEY
129.
()scillation
at higlr
frequencies
after usual tests have
shown
up
nothing
. Check value
of fixecl
portion
of
volume corrtrol.
It
should
be
200 ohnrs and is critical. If necessary,
put
irr a 25
olrnr
resistor iu
series,
rais-
ing the
value
of
the tixcrl unit to 22.5
ohrus.
CROSLEY
130. Dial
off
frequency,
or
frequency
settings
"drift"
. .
.
Do
not
adjust
oscillator trimmer until
you
are
sure
the dual
filter and
screen
grid
8 and 4 mfd.
condenser
is not leaky or
open.
Original unit breakdown
voltage
is 300 for
the
filter section, 150 for
the
screen. Replace with
450
volt and
200
vott sections.
(IF
181.5 kc.)
CROSLEY
130.
(Jscillatron,
lack
of
volume,
hum
Check for failure
of 4 mfd., 300
volt section
of dual card-
board
type dry electrolytic.
Use a
450
volt
job
in this
position.
CROSLEY CHIEF
t32.
When
this lz-tube super
plays,
but volume
is
shy
and all
tubes,
voltages check ok
. . .
Unsolder
.0001
condenser between
cathode of 56 used as diode
detector and
5
meg. resistor and check
it for
a
short.
This trouble is difficult
to locate and
relatively
common.
CROSLEY I43
Distortion
open
Since
this
feeds bias
tube, an
open circuit
bias.
tone control.
to the
driver
removes the
CROSLEY
146.
Local
statious
re-
..iu"J
*."t
ly,
voltages
ok
'
Look
i.i
tir""
tz
ntike'coridenser
section
of
dual
'filter
and
cathode
6
mike
card-
bo"i.l
.tt."..d
unit.
lteplace,
if
"out"
with
l2
nrike
400
volt
job.
Lower
breakdowrr
rrnits
will
trot
last.
CROSLEY
148. Dead, or weak signal
.
Generally due
to increased value of
wire-wound,
impregnated
resistor
under
chassis from i.f. coil
to
plate
and cathode
of 58.
Replace with two-unit type with
an 8,500 ohm and a 25,000 ohm
resistor,
l0 watt types.
CROSLEY I48
Dead
check first
i.f.
pl:rte
trimnrer fr-rr short to
grourrrl.
Repl:Lce
trirrrrrter
or
itrst'rt
ncw
lrric:r.
CROSLEY
148. If set cuts out
or
works
poorly
on
low line voltage replace
2.5 volt
pilot
with a 6-volt bulb.
The
pilot
is
wired
across the 6.3
volt tube
circuit and sonretinres
reduces
heater
voltage to below nornral.
cRosLEY |48
Intermittent
reception
High
re-
.sistance
short
often
develops
in
the
padding
condenser
due
to entry of dust
and dirt. Clean
with carbon
tetra-
t:hloride.
CROSLEY
148.
Periodic drop
rn
volume,
distortion.
See
if the twin
cub
condenser in resistance-coupling
net-
work between detector and
a.f
.
is
re-
versed. The .03 should
be
the coupling
condenser between
57
plate
and
42
input
grid.
One terminal
of
the .001
should
be
grounded
and the other
connected
to
the
detector
plate.
Some
condensers
have wrong markings and
the
.001 is in-
correctly connected between
ground
and
a.f. tube
grid.
CROSTEY
|
'18-FIYER.
Set dead
below
1,200 kc.,
volume
con-
trol
inoperative
after
half revolution,
oscillation
over
entire
band
. . .
Suspect
the 6-8 electrolytic
and
substitute an-
other
for test as
it sometimes shows
up
ok
with respect
to
leakage and
still
causes trouble.
Use
a hisher break-
down
type.
CROSLEY
148,
167, 169. No reception,
voltages ok . . . Sonretinres due
to
short-
ing of internrediate
transformer
tuning
condenser
suspended
in
square hole cut
in chassis between 58's. Caused
by
punc-
ture of nrica spacer when
screw is
driven
down
too tight.
Slip snrall
piece
of
mica
under hinge
part
of
condenser
plate
and
re-align. Also check
for similar
trouble
in the
other
postage-stanrp
condenser
located on top of tlre
chassis.
Oscitla-
tion
Try a .02, 600 volt condenser
from
ground
to
power
transformer
side
of a.c. sn'itch. Never use a
2.5
volt
pilot
in chassis having
42
tube as this causes
fading;
stick
to
6.3 or 6.8
lanrps.
t7