TM 11-6625-2629-14&P
Table 7-3. General Support Troubleshooting Chart -Continued
Correction
Probable trouble
Symptom
Check and replace any defective part
Defective components within T9.
in T9.
Replace switch S4 (para 7-21).
Faulty contacts on switch S4.
Replace defective components.
Defective meter M2 or associated
C h e c k and replace any defective
7. W i t h
unmodulated
input,
Unstable local oscillator caused by
component in the local oscillator
D E V I A T I O N meter M3 reads
defective component in local
circuit.
some amount of deviation.
oscillator circuit.
Replace defective tube.
8. F r e q u e n c y - m o d u l a t e d s i g n a l
Defective tube V10, V11, V12, or
V13.
applied to input. LIMITING and
Defective
c o m p o n e n t i n audio
C A R R I E R SHIFT meters read
Replace defective component.
amplifier circuitry.
correctly .
DEVIATION meter
Faulty contacts in switch S4.
does not read. No audio output at
Replace switch S4 (pars 7-21).
AUDIO OUTPUT terminals.
9. W i t h
modulated
Replace V 13.
Defective tube V13.
carrier,
DEVIATION meter readings are
Measure voltages and resistances (fig.
Defective component in V13B circuit.
7-4 and 7-5).
present; no audio output.
Replace defective component.
Defective tube V13.
Replace.V 13.
10. With modulated carrier, no
Replace meter M3.
Defective meter M3.
DEVIATION meter readings are
Defective components in V13A
Measure voltage and resistance (fig,
present; voltages are at AUDIO.
7-4 and 7-5).
circuit.
Replace meter M1.
SHIFT
and
11. CARRIER
Defective meter M1.
Replace R51.
DEVIATION meter readings are
Shorted potentiometer R51.
Replace C54.
normal. No limiting indication on
Shorted capacitor C54.
LIMITING meter. Adjustment of
R51 has no effect.
of
R51
Adjust R51 ADJ.
Improper
adjustment
SHIFT
and
12. C A R R I E R
DEVIATION meter readings are
(LIMITING ADJ).
Replace R51.
normal. LIMITING meter needle
Open potentiometer R51.
is pegged at top of scale.
Replace
R73 or R74.
13. W i t h modulated signal input,
Resistor R73 or R74 open.
Replace
C83 or C84.
Capacitor C82 or C83 shorted.
LIMITING and DEVIATION
Replace
meter M2.
m e t e r readings a r e c o r r e c t ;
Defective meter M2.
Replace
switch S4.
CARRIER SHIFT meter does not
Defective switch S4.
read as TUNING control is
varied.'
Warning: The 5651 WA tube contains
Defective power supply.
14. With modulated signal input, all
radioactive
material.
Handle
meters do not read.
carefully to avoid breaking. Check
all power supply components.
Replace CR1.
Defective mixer diode CR1.
Check all components in the local
Defective oscillator stage V1.
C h e c k t u b e a n d voltage and
Defective if amplifier stage V2.
resistance readings (fig. 7-4 and 7-
5).
Check voltages and resistances (fig.
Defective integrated circuit V1 (assy
7-5) .
MP-14663).
7-7
