Section IV. MAINTENANCE, REPAIR AND REPLACEMENT OF AUTHORIZED PARTS

TM 55-4920-411-13&P

4-5. Repainting and Refinishing Instructions.

(2) Case (exterior). Finished with two coats of

yellow baked enamel, item 2, App. D.

NOTE

(3) Instrument Deck (front only). Since deck is

Refer to TM 43-0139. Painting Instruc-

photo-etched, it cannot be refinished. Retouch using

tions for Field Use.

instrument black enamel, item 3, App. D Enamel is then

covered with one coal of clear, flat lacquer.

a. Repaint test set using these colors:

(1) Case (interior). Finished with two coats of

gray baked enamel, item 1, App. D.

Section IV.

MAINTENANCE, REPAIR AND REPLACEMENT OF AUTHORIZED PARTS

4-6.

Maintenance.

Bezel Assembly

(7)

a. The only authorized replacement of authorized

Remove six screws holding bezel as assembly to

deck.

parts by Aviation Unit personnel (AVUM) is indicated

in App B. Maintenance allocation chart and identified

(8) Lubrication.

below. (Knobs, lamps seconds display and fuse).

None is required.

(1) Knobs.

Knobs for VAR FREQ ADJ (f1) switch and FUNC-

b. Authorized repair of the Temperature-Speed Simu-

TION SWITCH (S2) are both attached using two socket

later Test Set by Aviation Intermediate Maintenance

head setscrews, that are included with the knob.

(ATST) personnel is indicated in App. B, Maintenance

Allocation Chart.

(2) Power Lamp.

The power indicating lamp, immediately above the

half-ampere fuse, is replaced by unscrewing the yellow

NOTE

lamp cap and lifting out the malfunctioning lamp

Aviation Intermediate Maintenance

(3) Seconds Display.

(ATST) will perform only the authorized

Remove seconds display as follows:

maintenance which includes replacement

and repair of components and end items

(a) Remove six screws holding display bezel to

which can be accompanied efficiently with

deck, and remove bezel.

available skills, tools, and test equipment.

(b) Gently lift malfunctioning display package

Evacuate circuit boards. components, and

from board, and replace with a new package

end items beyond capability of ATST to

the Depot.

replace screws if seals are worn.

NOTE

(d) Inspect and replace bezel if damaged.

Perform paras 4-8, 4-9, and 4.10 as direc-

(4) Fuse.

ted by troubleshooting table 4-3 and

Waveform Test points table 4-4 or as ap-

The fuse is replaced by unscrewing the fuse cap

plicable. Schematic diagrams and assem-

and lifting out the malfunctioning fuse.

bly boards are listed in figures 4-1 through

(5) Power Lamp Lens.

4-6. Do not replace circuit board if repair

can be accomplished for authorized re-

Unscrew and remove power lamp lens.

placement components on display and sig-

(6) Cable Assemblies.

nal generator boards.

Remove cable assembly from Simulator case and

send to higher maintenance.

4-3