REMOVAL AND REPLACEMENT OF PARTS ON THUMBWHEEL SWITCH ASSEMBLIES.

T.O. 12P4-2APX-142

NAVAIR 16-35C6280-1

TM 11-5841-268-25

remove wafer from shaft. Check that flats on sides of shaft

that holds switch assembly to angle bracket (49, FO3; p/o

are vertical, as shown in Figure 81, and reinstall shaft in

65, FO-4; 51, FO5).

hole in chassis (15), making sure the gear teeth mesh with

Step 3. Remove two flat-head screws (58, FO3; 61,

the teeth of the gear on the chassis assembly.

FO-4; 60, FO5) that hold switch to subassembly mount-

Step 3. Apply a small amount of Lubricant 551D7-44 to

ing panel (59, FO3; 65, FO-4; 61, FO5).

gear teeth, as necessary. Remove any excess lubricant.

Step 4. Remove thumbwheel switch assembly.

Step 4. Position insert of switch wafer as shown in FO-1

Step 5. To install thumbwheel switch assembly, reverse

and Figure 81 (flat side vertical, notch toward front of

the procedures in Steps 2 and 3.

switch assembly), and install wafer on shaft of shaft and

gear assembly.

Step 6. See wiring diagram FO2 and solder wires to

thumbwheel switch assembly.

Step 5. Replace washers (7), spring tension clip (6), and

screws (5).

Step 7. Replace the plastic light panel and rear panel as-

sembly (paragraphs 83 and 85).

822. REPLACEMENT OF INDICATION KNOB ASSEM-

BLY. Except for S212, to replace the indication knob as-

8-19. REMOVAL AND REPLACEMENT OF PARTS ON

sembly (9, Figure 81), check that the knob is set to "7,"

THUMBWHEEL SWITCH ASSEMBLIES.

as shown in Figure 81. For S212, set the knob to "3."

820. GENERAL. To remove and replace parts on the

Then, proceed as follows:

thumbwheel switch assemblies, remove switch assembly from

Step 1. Using C-ring expanding tool, carefully spread re-

transponder set control (paragraph 817). Refer to the ex-

taining ring (10, Figure 81). Remove ring, flat washer or

ploded view in Figure 81 and to the appropriate procedure

washers (11), and spring washer (12).

in paragraph 8--21 or 8--22 for parts replacement. When the

Step 2. Lift indication knob (9) and spur gear (13), which

repair is completed, reinstall the switch assembly.

is attached to knob, from shaft.

821. REPLACEMENT OF SWITCH WAFER. To replace

Step 3. Install spur gear on replacement indication knob.

the switch wafer of the rotary switch (4, Figure 81 ), check

Step 4. Apply a small amount of Lubricant 551D744 to

that indication knob assembly (9) of all switches, except

gear teeth, as necessary. Remove any excess lubricant.

S212, is set to "7." Set S212 to "3." Then, proceed as

follows:

Step 5. Orient spur gear and indication knob as shown in

Figure 81 (flat sides in gear vertical), and install knob and

Step 1. Remove two screws (5), spring tension clip (6),

gear on shaft.

and two washers (7) that fasten switch to chassis ( 15).

Step 6. Replace spring washer (12), flat washers (11) as

Step 2. Lift switch wafer from shaft of shaft and gear

required, and retaining ring (10).

assembly (8). If shaft and gear assembly lift up with wafer,

Figure 81. Thumbwheel Switch Assembly, Exploded View