Replacement of Parts - TM-11-6625-542-14-10035

TM 11-6625-542-14-1

(5) A carelessly soldered connection may

(2) Disconnect radio frequency cables from

create new faults. It is important to make well-soldered

front panel.

joints because a poorly soldered joint is one of the most

(3) Remove side covers from AN/USM-108A

difficult faults to find.

by turning two locking screws on each side of chassis,

(6) Replace parts in the circuit in exactly the

disengaging the covers at the bottom of the chassis and

same position occupied by the original part. A part that

removing covers.

has the same electrical value but different physical size

(4) Remove six screws from front panel; one

may cause trouble. Give particular attention to proper

in each corner and two securing the nameplate to the

grounding when replacing a part; use the same ground

front panel.

as in the original wiring. Failure to observe these

(5) Remove grounding lug from front panel

precautions may result in decreased output or parasitic

by removing screw at rear of lug.

oscillations.

(6) Unscrew lenses from indicator lamps on

(7) Do not disturb any of the alignment

front of panel; note color.

adjustments unless it definitely has been determined that

(7) Remove retaining nut from POWER ON

the trouble is caused by an adjustment.

switch.

(8) Remove retaining nuts from rear of

indicator lamps.

6-9. Replacement of Parts

(9) Remove front panel and trim strip.

The components of AN/USM-108A are easily

Assembly.

reached and replaced if found faulty. The transformer,

(1) Position front panel and trim strip onto

reactors, and terminal boards are mounted securely to

chassis.

the chassis with hexagonal nuts and machine screws.

(2) Position indicator lamps through front

If any of the switches require replacement,

panel and secure in place with retaining nuts.

carefully mark the wires connected to the switch with

(3) Position POWER ON switch through front

tags to avoid misconnection when the new switch is

panel and secure in place with retaining nut.

installed. Follow this practice whenever replacement

(4) Screw proper-colored indicator lenses

requires the disconnection of numerous wires.

onto indicator lamps.

For tube replacement techniques, refer to

(5) Install grounding lug in front panel and

paragraph 6-7.

secure with nut on rear of panel.

Refer to figure 6-5 (1) through (11) for

(6) Position nameplate on front panel and

location of parts.

secure in place with two screws.

6-10.

Disassembly and Assembly of Front

(7) Install four screws in corners of front

Panel

panel.

Disassembly. Disassembly of the front panel

(8) Install side covers in position at bottom of

is necessary if any of the front panel switches are

chassis and secure in place with two locking screws on

repaired or replaced. Follow the procedure outlined

each side cover.

below:

(9) Connect cables as required.

(1) Disconnect power cable from source and

from AN/USM-108A.

6-11