Operating instructions

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procedure
and to
determine the defective
cir-
cuit.
A
tube check
and voltage and resistance
measurements
in the
circuit
ordinarily should
be
sufficient
to
isolate the defective
part.
a. Sectionali,zí,ng
Trouble.
rM
295-36_
Note.
In
the
following
tests,
the
power
supply
is
connected
to the
receiver, the
poll'er
is
turned
on,
and
the
power
supply
is operative.
Set
the
receiver eon-
trols as in the
preparatory
section
of
the
equipment
per-
formance checklist.
Figure
35. Power Suppla
PP-30SlURR,
top aiew of
chassis,ui'th coaerremoueil.
Symptom
Probable
trouble
Correction
Dial
lamp
inoperative
when
DIAL
LIGHT
switch
SB
is dePressed'
No
receiver
output,
but dial
lamp
lights
when
SB
is dePressed.
Receiver
operative,
but excessive
hum
in loudspeaker
or
headPhones'
No
signal
in loudspeaker
and
headset,
with
a
signal
fed
from an
audio
oscillator
through
a
'05-pf
capacitor
Defective dial lamp. Defective
filament
circuit.
Defective
switch S3.
Defective
tube.
Defective
loudspeaker
or headset.
Defective
filter
capacitor C114,
C118
(power
supply), or C37
(receiver).
Avc
circuit open, R15 or R18
open,
Faulty a-f stage.
Repair
or replace
defective
part.
Check
tubes.
Repair
or replace
de-
fective
part.
Replace
defective
part.
Check tubes.
Use
signal
substitution
in the audio stages
(par.80).
Re-
pair
or replace
defective
part.
Check
tubes.
Use signal
substitution
in i-f
stages
(par.
81). Repair
and
replace
defective
part.
to
pin
6 of V6'
No
signal
output
in
loudspeaker
and
I
Faulty i-f or detector stage.
headset,
with
a
modulated
455-kc
j
signal
from
a signal
generator
I
coupled
to
pin
6
of
V3
through
a
I
.01-pf
capacitor,
PHN.-C.1V.-NET'
I
CAL.
switch
52
set
to
PHN.
Posi-
|
tion, and
audio
stages
checked'
I
60
AGO 813r\
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