CHAPTER 6. DIRECT SUPPORT MAINTENANCE INSTRUCTIONS

TM 11-5985-355-13

CHAPTER 6

DIRECT SUPPORT MAINTENANCE INSTRUCTIONS

Section I. TROUBLESHOOTING

5120-00-568-4742).

6-1. Scope of Direct Support Maintenance

b. Test Equipment.

The direct support maintenance instructions supplement

(1)

Receiver-Transmitter,

Radio

RT-

the maintenance procedures covered in the technical

524/VRC, or RT-246/VRC.

manual for the radio set with which the AS-2731/GRC is

(2) Wattmeter AN/URM-120.

used. A troubleshooting chart is given in paragraph 6-4;

(3) Multimeter TS-352B/U.

repair procedures are given in paragraphs 6-5, 6-6, and

c. Materials. Refer to appendix E for materials

6-7, and performance test procedures are given in

required for direct support maintenance.

paragraph 6-8.

6-3. Direct Support Maintenance Trouble-

6-2. Tools, Test Equipment, and Materials Re-

shooting

quired

Perform the applicable direct support procedures as

The following tools, test equipment, and materials, or

outlined by the technical manual for the radio r/T unit

appropriate equivalents, are required to perform direct

used with the AS-2731/GRC. If the AS-2731/GRC is

support maintenance:

defective, perform the troubleshooting procedures given

a. Tools.

in troubleshooting chart (table 6-1). If the corrective

(1) Tool Kit, Electronic Equipment TK-

measures given in the chart do not clear the trouble,

101/G.

higher category of maintenance is required.

(2) Tool Kit, Electronic Equipment TK-

100/G.

(3) Torque screwdriver, 0-Z5 inch-lb (NSN

Section II. REPAIR PROCEDURES

and duplicate the original position after repair.

6-4. General

6-6. Antenna Element AS-27321GRC Parts

This section contains direct support repair procedures for

the AS-2731/GRC.

Removal and Replacement

a. Antenna Element AS-2732/GRC. Repairs are

(fig. 6-1)

limited to the removal and replacement of certain parts

a. Contact (SM-B-542008).

(para 6-6).

(1)

Remove contact (SM-B-542008) by

b. Matching Unit-Base MX-9146/GRC. Repairs

removing two screws (MS51957-1).

consist of parts removal and replacement (para 6-7) and

(2) Replace contact (SM-B-542008) with the

performance tests (para 6-8).

screws removed in (1) above. Apply 1 or 2 drops of

6-5. Special Precautions

sealing compound (item 7, app E) after starting the

Observe the following precautions when

screws.

b. Contact (SM-B-542007) and Contact Spring

removing and replacing wires. When soldering or

Assembly Parts.

unsoldering wires, solder quickly to allow as little heat

(1)

Unscrew and remove ring (SM-B-

conduction as possible. However, avoid making a cold-

889201). Tap the AS-2731/GRC on the bench to

solder joint by first heating the joint where solder is to be

remove contact (SM-B-542007), insert (SM-B-542004),

applied. When wiring permits, use a heat sink (such as

and spring (SM-B-542006).

long-nosed pliers) between the soldering iron and a

(2) Replace the parts in the sequence

component.

Excessive heat may damage the

shown in figure 6-1 and tighten ring (SM-B-889201).

component.

b. Orientation of Parts. When an electronic part is

moved aside, note the position of the part and its leads

Change 2 6-1