Section III. TROUBLESHOOTING - TM-5-6675-309-140090

ARMY TM 5-6675-309-14

MARINE CORPS TM 08840A-14/1

Section III. TROUBLESHOOTING

b. Test Connections. Connect cables only when

8-7. General. Should malfunction of the PSTS be sus-

called for in the test procedures.

pected, perform test procedure in accordance with

table 8-5. The table is arranged in four columns. The

NOTE

first column contains the test operation to be per-

Incorrect connections can cause wrong

formed. The second column contains the normal indica-

indications. See figure 8-4 for electrical

tion to be observed when the procedure has been

connections.

performed. The third column contains the corrective

action to be taken if the normal indication is not

c. Procedure. Perform testing in accordance with

obtained. The fourth column gives the coordinates on

table 8-5.

the schematic diagram of the affected circuitry. When

performing corrective actions, refer to the PSTS sche-

matic diagram (figure FO-2) and wire list (table 8-1) to

determine where to make voltage measurements. For J2

Correct digital voltmeter scale must be

and J3 connector-pin locations, see figure 8-3A. See the

selected manually. The digital voltmeter

PSTS arts location diagram (figure 8-5) and exploded

does not change range automatically.

view (figure 8-6) for location of parts. Wherever a

NOTE

corrective action has been taken, the complete test

procedure must be repeated to verify repair. The self-

In the malfunction indication/corrective

test procedure must be followed in the order given.

action column of table 8-5, components

to be replaced are listed in order of most

likely failure. Verify component failure by

8-8. Power Supply Test Set Troubleshooting.

making voltage and resistance checks be-

fore replacement. After a component is

a. Test Equipment and Materials.

replaced, check for normal indication be-

f o r e attempting to replace another

(1) Digital Voltmeter AN/GSM-64B, or equiva-

component.

lent, for all voltage and impedance measure-

Indicators may light at various times

ments.

throughout this test. Unless listed in table

8-5 as a normal indication, disregard the

(2) Stopwatch.

lighted indicator.

If the corrective action does not eliminate

(3) Oscilloscope AN/USM-281A or AN/USM-

the malfunction, then check for parallel

273.

s h o r t i n g paths (e.g., shorted diodes,

shorted relay contacts, etc.)

(4) Multimeter AN/USM-233.

8-42