Technical information

O
RADIO
RETAILING'S
rrSevuie
AfRL|NE
62:2126
Dead
open secondary
of
an-
terrna
coil.
f,oil
rrust be renroved
to
6nd
tr-ouble.
AIRLINE
64. Inoperative
tuning
meter
and
weak signals. Place finger
on con-
trol
grid
cap of
first
r.f.
58. If volume
increases
meter
is burned
out. It
mav
be
shorted
without
afiecting
set opera-
tion until
a replacement
can
be
obtained.
AIRLINE
77-95.
Poor tone
quality
noted
after
replacing
defective 19 tube
. .
.
Change
bias
from
6 to
41. If in
cabte
disconnect
from
6 volt
pin
and
conncct
to
4l
volt
pin.
Static-like
noise
.
.
. Replace
push-pull
input trans-
former.
IF:175.
AIRLINE I82
Power
transformer
lreats badly
after
a few minutes
operation filament
leads to various
tubes
are
trvisted to-
gither
and bunched
close
to chassis,
sometimes shorting to i,t. To
test
unsolder centertap of
filament
winding
fronr
ground
and check continuity. Any
reading indicates
a short.
AIRTINE
I98
Inoperative
open
.l
nrfd con-
denser
connected
between wave band
switch and first lug
(from
front of
set) on rack
of three trimmers mounted
on coil assembly.
AIRIINE
203
Dead.
.
Test
the
condenser and
resistor located
behind
the volume
con-
trol.
Replaces resistor
with 500
ohm
I
watt unit and
condenser
rvith .25
mfd 400
volt type.
AIRLINE 2O9
Erratic
operation, sornetimes dead
on
s.w.
bands clean band switch
contacts
with carbon
tetrachloride.
AIRLINE 2I I
Distortion.
Replaces
defective
resistor
in
plate
circuit
of 3.1 detector
with 40.000
ohm unit.
AIRLINE 225
Intermittent
distortion
aftel several
hours
of operation
check for
warping
of voice coil.
AIRLINE
320
Distortion
at lorv volunte
change the
.5
meg
second
detector
screen resistor (R5)
to .7 meg.
AIRLINE
403
Distortion check 15 nrrnf
i.{.
coupling conrlensers
for
change
itr
ca
pac
i t1'.
AIRLINE
504
Irrolrclrrtir-r:
at lou'
frcr;ucttcv ettd
of
rli:rl
chrtrgt'oscillator
gritl
1e:tk
it-,,'',r
J{).tX)0 to
.50,()00
ohnrs.
8
AIRLINE
Alc:andcr. If
you
can't
align
check center-tap resistor
of 2l-volt
winding. It
should
be
150-ohms but
sometimes
changes valrre enough to
cause osciJlation.
AIRLINE, GULBRANSEN 9.
Severe
cases of oscillation arc curable
by
removing
the
gang-condenser
rotor-
rod,
sandpaperirrg
it where it
contacts
the
frame,
sandpapering
spring
contacts
and
adjusting screw.
AIRLINE T.R.F.
Poor tone
connect a
10,000
ohnr resistor across
primary
of
p.p.
input. Also
.02
mfd
from
plate
ter-
nrinal
of
primary
to one side
of sec-
ondary.
AIRLINE
I955
Intermittent
replace
.01
mfd.
coupling
condenser
between oscillator
plate
and
grid.
This
condition
can be
checked by
testing
for
oscillator
signal.
AIRLINE. Fluctuating
filament
volt-
ages
in
older
models
using 26's,
or
failure
of
r.f.
tubes to light at all.
Caused
by loosening
of
riveted
junction
between
binding
posts
and
power
translormer
lead
soldering
lugs, due to
shrinkage
of
mounting
strip. Remove transfornrer
and flood
riveted
junction
with solder.
Some local-distance
switches test all
right
on ll0
volts but
fail
to make con-
tact when
in actual use.
Clean
hardened
flux
or
grease
from contacts.
APEX
APEX 8A,
10.
Distortion,
after
set
has
played
for
about 30 minutes,
47
grid
gets
red Caused by
open
47 fila-
ment center-tap, Usuatly it is
just
an
intermittent open.
Sudden
increase in
volume, or decrease, when nearby
light
is turned
on Generally
caused
by
an open .5
mfd.
condenser
connected be-
tween r.f. cathode and
grid
return of
r.f.
and
i.f. coils.
Replace with
400
volt
un
it
APEX 7
Interrnittent
on
low {r'equency
enrl
o{ dial
check
filter
concleusers
for clecreasccl c:rpacity.
APEX 7
Live
sound
when antenna
post
is
touched
but
no reception.
. . . Check
20,000
ohm
second
detector
bias resistor.
A
sirnilar condition may tre caused
by
1,800
ohm section
of
bleeder resistor.
APEX IO
Inoperative,
nornral rvith 27 a.\'.c.
tube
out of socket
replace
180ti
ott',t ra61irrll
of Cattrl,rlrnt resistor';rt
lrAr'
of
cltar::r.
APEX
26
Hi.qh
screen
voltage orr
rletector tubc'
replace
2640
olrm section of
arnroretl
resistor
with
2,500
ohnr
l()
rvatt rvirs \\'oun(l
resistol'.
APEX 26
No
reception,
smoke f rom trans-
former
,
unit its€lf
perhaps
not
at
fault.
Cause is sometinres
faulty in-
sulation
on wires in cord-bound
cable.
To
check this,
remove
chassis frorn
cabinet
and turn chassis
upside
down.
Switch receiver
on and
at same
time
watch
cable closelv:
there will
likely
be a spark
or flash noted
at
point
where
rr,ires are
shorting.
APEX
26
No r.f. screen volts.
. Check
black wire
at
speaker for voltage; no
voltage
indicates open
tap
on speaker
field.
To repair:
tap screell
voltage
through
a
I
watt
resistor
from the red
lead
that
feeds
the
r.f.
transformer.
Screen
voltage
should read about 80
volts
after
repair.
_
AP&X
,27.
Intermittent
oscillation.
Increase
the
r.f.
by-pass
condenser
from
t
to
I
mfd.
APEX 27, 27P
Part
subject
to breakclown
long
(-:rnrlohnr
lesistor
at inside rear
of cha.:is. Ohnrdge
of sections
be-
ginnirrg
rvith
that
fed frorn
filter
cholie:
.+.700,
8,400
ancl 10,700
ohnls.
APEX 3I
Rum
ling
noise
when
set is
jarred.
.
. .
tighten
the
r.f.
chokes
located
in-
side
the r.f. coils
by
cementing
with
an
acetate
base cement
or
jamming
with
a
toothpick.
APEX 32
Fading, intermittent
lrorvling.
Flat blpass
condenser
can
contairrirrs
6
conderrsers
has
poor
groutrd
connec-
tion.
Can
is
colllnlon, sokler
can
t<,
tube shields.
APEX 36
Norur:rl
('r
excessive
volunre
at hiqh
end of
clial, rveak on other
en(l
replace
open antenna choke
antl realiqn
se
t.
APEX 46. Distortion on low
volume
after tubcs are
replaced
Remove
old
volume
control, which
is
simply a cathode resistor in the 24 cir-
cuits, and
replace
with
10,000
ohm
tapered unit, connecting one side to
antenna lead,
center arm to
ground
or
chassis,
other terminat
to cathodes of
24's through 250 ohm 6xed resistor.
Break in
wire Wound
resistor where
old
controt was connected should be closed
with
jumper.