TROUBLESHOOTING CHART (Cont)

TM 11-5805-387-34-2

MALFUNCTION/SYMPTOM

PROBABLE CAUSE

TEST PROCEDURE

INDICATION

YES

Do all continuity and resistance checks with all power removed.

2. Remove module A4 (para 2-8).

Continuity

Go to 3.

Replace

Check continuity of relay K1 with MODE

defective

SELECTOR switch at positions 850 HZ

relay K1

and 85 HZ (fig. FO-8).

(para 3-9).

3. Replace module A4; set MODE SELECTOR

Input signal

Go to 4.

Replace

switch at 85 HZ DIVERSITY. Connect

present on

defective

TS-799AIUGM-1 (para 2-4) and test

AN/USM-281A

filter FL6

cable No. 3. Check for signal continuity

(para 3-9).

across terminal 1 of filter FL6 (fig. FO-8).

4. Set MODE SELECTOR switch at 850 HZ.

Input signal

----------

Replace

Check for signal continuity across terminal

present on

defective

3 of filter FL7 (fig. FO-8).

AN/USM-281A

filter FL7

(para 3-9).

(13) RCV LEVEL READING ON METER M1.

Defective: Mode selector switch S4. Filter FL4.

RECEIVE TTY MALFUNCTION

Relay K1. Filter FL6. Filter FL7.

Do all continuity and resistance checks with all power removed.

1. Check continuity of MODE SELECTOR

Continuity

Go to 2.

Replace

switch wafer S4D (fig. FO-8).

defective

switch S4

(para 3-8).

2. Set MODE SELECTOR switch at 85 HZ

Input signal

Go to 3.

Replace

DIVERSITY. Connect TS-799A/UGM-1 (para

present on

defective

2-4) and test cable No. 3. Check for

AN/USM-281

filter FL4

signal continuity across terminal 2 of filter

(para 3-9).

FL4 (fig. FO-8).

3. Check for signal continuity across terminal

Input signal

Go to 4.

Replace

4 of filter FL4 (fig. FO-8).

present on

defective

AN/USM-281

filter FL4

(para 3-9).

3-14