General Parts Replacement Techniques

11-6130-243-14-3

d. Troubleshooting Chart.

Corrective Measures

Probable trouble

Symptom

Item No.

Check for correct input voltage.

No ac power applied to power supply.

PILOT LIGHT does not light when

Replace lamp.

PILOT LIGHT lamp burned out.

CIRCUIT BREAKER is set to ON.

Check C B1, replace if necessary.

CIRCUIT BREAKER CB1 defective.

Open in output circuit.

Check for loose connection, broken lead,

No output voltage present.

or faulty component.

b. Replace power transformer T1.

b. Defective power transformer T1.

a. Replace switch S1.

a. Defective switch S1.

Output voltage does not change when

b. Replace power transformer T1.

b. Defective power transformer T1.

OUTPUT VOLTAGE ADJUST switch

is turned in a clockwise direction.

Replace defective rectifier.

Defective rectifier CR1 or CR2.

Low output voltage as indicated on

Replace transformer T2.

Defective transformer T2.

VOLTS meter.

Replace VOLTS meter M2.

Defective VOLTS meter M2.

Indication on VOLTS meter differs from

Check Cl, replace if necessary.

Defective capacitor Cl.

the voltage measured at the output

terminals using AN/USM-223/U.

Replace AMMETER SWITCH S3.

Defective AMMETER SWITCH S3.

indication on AMPS meter Ml does

not vary as OUTPUT VOLTAGE AD-

Defective AMPS meter Ml.

Replace AMPS meter Ml.

Defective meter shunt R2.

Replace meter shunt R2.

JUST switch is turned in a clockwise

Adjust or replace potentiometer R3.

Maladjusted meter Ml.

direction with AMMETER SWITCH

held in ON position.

hold handle to frame.

5-5. General Parts Replacement Techniques

(4) Remove 14 screws and washers holding side

a. Removal of Top Cover. Remove four screws and

panel to frame.

washers from top cover and lift top cover away from

(5) Slide side panel away from handles until

power supply.

clear and then lift away.

b. Removal of Side Panels.

c. Parts Replacement. Power supply parts can be

(1) Remove top cover (a above).

reached and replaced without special procedures after

(2) Remove two screws and washers from center

the top cover and appropriate side panel have been

of side panel.

removed.

(3) Remove two bolts, washers, and nuts which

Section Il. TEST PROCEDURES

testing procedures given in this chapter are listed in a

5-6. General

and b below:

a. Test

procedures are prepared for use by

maintenance shops and service organizations respon-

a. Test Equipment

sible for general support maintenance of electronic

equipment to determine the acceptability of repaired

Nomenclature

NSN

equipment. These procedures set forth specific re-

quirements that repaired equipment must meet

Multimeter AN/USM-33(*)

662500-648-9172

Multimeter, AN/USM 223/U

6625-00-999-7465

before it is returned to the using organization, A sum-

(RSTS-352B/u)

mary of the performance standards is given in

Multimeter, ME30 ( )/U

6625-00-669-0742

paragraph 5-10.

Dummy Load, Electrical DA 638/U

662500-422-2111

b. Comply with the instructions preceding each

chart before proceeding to the chart. Perform each

b. Tools. All the tools required are included in Tool

step in sequence. Do not vary the sequence. For each

Kit, Electronic Equipment TK105/G and Tool Kit,

step, perform all the actions required in the Control

Electronic Equipment TK101/G.

Settings column; then perform each specific test

procedure and verify it against its performance stan-

58. Physical Test and Inspection

dard.

a. Test Equipment and Materials. None Required

5-7. Test Equipment and Tools

b. Test Connections and Conditions. Make sure in-

All test equipment and tools required to perform the

put power line is disconnected.

5-3