Operating instructions

paclror
C31, resistors
R19A
(A.F.
GAIN control),
R18,
R20,
R21,
and
capacitors
C32 and
C33.
b. Lotu
Output. Turn
OUTPUT
HIGH-LOW
srvitch
54 to LOW
and
apply
signals
as
in c,
above.
(1)
Apply
audio
signal
to
pin
2
of Y7.
Listen
for
a
weak
output
signal
(rela-
tive to
signal in
o
above)
in the head-
set
or loudspeaker.
If no
signal is
heard,
check
C42
and Tl4.
(2)
Apply
audio
signal
to
pin
6 of
VZ.
Listen
for
an
increased
output signal
(nelative
to
signal
in
(1)
above) in
the headset
or
loudspeaker.
If
the
signal
is weak,
check tube
V7,
resis-
tors R31
andR27,
and capacitor
C46.
81.
l-f
Signol
Substitution Tests
Set the
R.F.
GAIN and the
A.F.
GAIN con-
trols
to the maximum
clockwise
settings,
and
set the PHN.-C.W.-NET-CAL.
switch
to the
PHN.
setting. Adjust
the
signal
generator
to
455
kc
with a 400-cycle
modulation
applied.
Feed this
signal in
series u'ith
a .05-pf capaci-
tor into
the set at the
points
indicated
in o
through
I
below,
in
turn, and listen for
the
sig-
nal
in the
speaker
or headset.
An increase
in
signal
should
be
noted
when
a signal
is fed
at
the control
grid
as compared
to
the
plate
of a
particular
tube.
Note,
Iî it
is
determined
that
the receiver
is mis-
alined, refer
to
paragraphs
94,
95, and
96.
a. Termínal
t+
of V6
(Detector
Plute).If.
there
is
no signal
or
if
the
signal
is
distorted,
check resistors R17
and R18
and capacitors
C29
and
C30.
If
there is no signal,
the
secondary
winding
of T11 may
be open,
the capacitor in
the transformer may be
shorted,
or the trans-
former
may be misalined.
b. Termínal
2 of V5
(Plate
of
Second i-f
Amplifi.er).
If there is no
signal, the
primary
of T11 may
be open, misaìined,
or
shorted.
Check
the winding
and
internal capacitor.
c. Terminal 6 of
V5
(Grid
of
Second i-f
.A,mplifi,er).
If there
is no
signal,
check the tube,
he
plate
and screen voltages, resistor R16,
and
rrpacitor
C28.
The secondary winding
of trans-
{
)rmer
T10 may be shorted or misalined
;
capac-
,ror
in
transformer
may be
shorted.
66
d.
Terminal
2
of VI
(Plute
of Fi,rst
i-f Am-
plirter).
If
there is no
signal, check
the
primary
of
transformer
T10.
It may
be open,
shorted,
or
misalined.
Check
the winding,
and check
the
capacitor
in
the
transformer.
e.
Termùnal6
of Vl
(Grid
of First
i-f Amplt-
fter).
If
there is
no
signal, check
the tube
and
the
plate
and
screen
voltages
at
the tube.
Check
resistors
R10
and R32
(R.F.
GAIN)
and capac-
itors
C4 and
C23. The
secondary
of T9 may
be
open,
shorted,
or misalined.
Check the winding
and check
the capacitor
in
the
transformer.
f
. Termi,nal2
of VS
(Plate
of
Conaerter). if
there
is no
signal,
check the
primary
of T9. It
may
be
open, shorted,
or misalined.
Check
the
winding
and
check the capacitor
in
the trans-
former.
82. R-f
Signol
Substitution
Tests
(figs.
24
and 48)
Set the
signal
generator
to
1.5
mc with
a
400-cycle
modulation
applied through
a
110-
ppf
capacitor
to the
points
listed in
a, through
/
below.
Set the receiver
controls
as follows :
R,F.
GAIN control
A.F.
GAIN control
PHN.-C.W.-NET-CAL.
switch
BAND
SW.
switch
MANUAL-PRESET
TUNING
control
Maximum
clockwise
Maximum
clockrvise
PHN.
Band
1
1.5 MC.
a. Termi,nal
6 of VS
(Grid
of Conaerter).
(1)
Tune
the receiver for
an output
signal
in
the loudspeaker
and headset.
If
there is
no
signal,
the
r-f
section
of
the
tube
may
be
inoperative.
Check
the tube,
plate,
and screen voltages,
resistor R9,
and capacitor
C21. The
grid
circuit
may
be
shorted.
Check
resistor R7, capacitors
C18, C19, and
C1C, and
BAND
SW.
switch
51.
The
C
winding
of transformer T3 may
be
misalined,
open, or
shorted, or the
capacitor connected in
the
trans-
former may
be shorted.
(2)
The h-f
oscillator
may
be inoperative.
Check the tube. IJse a vacuum-tube
voltmeter
to
measure
the
grid
voltage
A
tl
P,
ls
ci
L-
AGO 3134