Operating instructions
รณ. The resistance
between
terminal
11
and
terminal
10
of J4
should
read almost
zero
rvith
all
tubes
in
place.
If the
reading
is
appreciably
higher, check
for an open
filament
line
from
pin
11
or an
open
ground
connection
from
pin
1.
c.
The resistance
between terminals
8
and
10
of J4
should
read 8
megohms. If the
reading
is lower
than this
value,
check resistors
R26,
P"27, and.
R30 and capacitor C40.
If capacitor
C47
is shorted,
the
input
resistance
will be
lower; check C47
and
resistors
R24 and
R31,
and
check
the rviring to
pin
J of
J1.
d. The resistance
between
terminals
9 and
10 of J4
should
read .5 ohm.
If
the
reading
is
higher
or
lower, check transformer
Tl4.
e. The
resistance
between 7
and
1 of J4
should
read
130 ohms.
If the reading
is differ-
ent, check
R23.
This
reading
will appear
at
pins
A and
B of JL.
/.
The resistance
between
A and C
of J1
should
read
125 ohms.
If the
reading
is incor-
rect,
check the
coil of
relay
K1.
g.
The
resistance
between
D
and
E
of
J1
should
be
1 megohm.
If the
reading
is incor-
rect,
check
R12, R36, and C27.
h. The
resistance
between
E and F
of J1
should
read
22.6 ohms.
If the
reading
is incor-
rect,
check
connections
to J2
and J3,
pins
A,
and
secondary
of
T14.
i. To
prevent
possible
damage
to the
power
supply,
correct
all
abnormal
conditions
before
connecting
the
receiver
to the
power
supply.
a.
Sectionalizing
Trouble.
75. Operotionol
Test
of
Power
Supply
PP-308/URR,
Operate
the equipment
as described
in the
equipment
performance
checklist
(par.
43).
This checklist
is important because
it fre-
quently
indicates the
general
location
of trou-
ble. Listen
for
cracking
or buzzing
noises which
indicate h-v arcing. Check
the
power
supply
for smoke and
for the odor
of burned
or over-
heated
parts.
76. Operotionql
Test
of
Rodio
Receiver
R-r74/URR
Operate
the equipment
as described
in
the
equipment
performance
checklist
(par.
43).
This checklist
is important
because
it fre-
quently
indicates the
general
location
of trou-
ble.
Listen
for signal
noise
in
the
receiver
or
for received
signals.
Depress
DIAL
LIGHT
switch to
check
filaments. Check
for h-v arc-
ing, smoke, and
the
odor of
burned
or over-
heated
parts.
77.
Trcuble-Shooting Chorts
for
Power
Supply
PP-308/URR
(figs.
35, 36,
antl
44)
The
following charts
are sltppliecl
as
ar-r aid
in locating
trouble
in
the
power
supply.
These
charts
list the symptoms
which the
operator
or serviceman
may observe
while
making a
few
simple
tests.
The charts
also
indicate
hotu
to
sectionalize
trouble
quickly
to
a
partictt'lcLr
stage
or circuit.
A tube
check
and voltage
and
re-
sistance
measurements
in the circuit
ordinarily
should
be
sufficient
to
isolate
the defective
part'
t-
l.
J
fn
l.r
::
Symptom
Probable trouble
POWER
ON-OFF
switch
in ON
position;
K101
is
not
actuated
for
1l5-volt a-c
operation;
set
inoperative
for arty
mode of
operation.
Vibrator
E101
or
E102
inoPera'
tive
for
6-, !2-,
or
24-volt
d-c
input.
or dead batteries.
Open
fuse
F101
(110V.1A.);
connecting
leads
to fuseholder
or
srvitch S103
broken;
switch
5103
defective;
defective
l-v
rectifier
cir-
cuit.
Open
fuse
F104,
F103, or
F102;
defective
5101 or 5103;
defective
vibrator
E101
or
defective
circuit
cotnponent.
input. Replace
batteries,
Replace
fuse
F101.
Repair or re-
place
srvitch
5103,
Check
relaY
K101.
Localize trouble
in
the
l-v
rectifier circuit
(b
belorv),
and
replace
defective
part.
Repair
or
replace defective
Part.
Localize
trouble
in
circuit
(b
be-
low), and
replace
defective
Part
No
voltage at
J103 for 6-,
12-,
or
24-volt
d-c
I
Check
power
source.
Check
Power
operation,
or
115-volt a-c
operation.
j
cable Assemblies cX-1355/U
and
I
CX-1359/U.
No
voltage at
J104 for
DRY
BATTERY
op-
Check
Power cable
Assembly CX-
eration; wrong
polarity
of d-c
line
voltage;
1
1360/U.
Reverse
polarity
of
58
AGO
3134