TM 55-4920-231-14
Table 5. Troubleshooting (Cont)
Shorted transformer or
Replace transformer.
rectifier. (Check continuity
Replace rectifier (paragraph 80).
and for shorts.) (See figure 10.)
Plug connector not secure.
4
Indicator light il-
Tighten plug connector
luminates but
motor does not run.
Open lead to motor. (Check for
Repair or replace wiring harness
continuity.) (See figure 10.)
(paragraph 85).
Open lead in motor. (Check for
Replace motor (paragraph 81).
Repair motor,
Replace brushes (paragraph 81).
Worn motor brushes.
Defective motor.
Replace motor (paragraph 81).
Repair motor.
Armature defective.
Repair or replace armature.
Open circuit in motor armature
Replace motor (paragraph 81).
or field winding. (Check
Repair motor.
resistance between motor input
and ground-approx. 1.7 ohms)
5
Motor runs slowly.
Worn brushes.
Replace brushes (paragraph 81).
Poor brush contact.
Seat brushers (paragraph 81).
Insufficient or incorrect oil in
Replace oil (paragraph 51).
reservoir.
Commutator worn or dirty.
Repair armature.
Defective motor bearings.
Replace bearings.
Lack of proper oil in reservoir.
Fill reservoir with proper oil
6
Pump is operating but
insufficient vacuum
or pressure is produced.
Clean check valve (paragraph 75).
Check valve stuck.
Clean or replace filter (para-
Filter clogged.
graph 74).
Clean lines (paragraph 63).
Line plugged.
Tighten connection (paragraph 68).
Loose connection.
Replace tube (paragraph 63).
Defective tubing.
Replace instrument (paragraphs
Defective instrument.
65-69) .
Adjust relief valve (paragraph 62).
Improperly adjusted relief
valve.
Tighten caps to prevent leakage.
Caps on connectors loose.
Defective pump.
Replace pump.
Replace valve (paragraph 64).
Defective selector valve.
Section V. RADIO INTERFERENCE SUPPRESSION
equipment is satisfactorily suppressed, there is no
57. GENERAL.
radiated or conducted interference in the fre-
Radio interference suppression is the elimina-
quency range of 0.15 through 1000.0 megacycles
tion, or reduction to a minimum, of electrical
at a distance of 5 feet from the tester.
disturbances produced by operation of the equip-
ment. These electrical disturbances are composed
partly of electrical waves in the radio frequency
COMPONENT.
range. They must be suppressed as they will in-
There is a filter (6, figure 19) mounted on the
terfere with the proper operation of friendly
electric motor (2) and it provides a low resist-
radio and radar equipment, and can be detected
ance path to ground stray currents created by the
by an enemy with electronic devices to give an
arc of the motor brushes.
accurate location of the equipment. When the
