TM 9-4120-357-14
4-32. Junction Box.
The junction box contains or supports the electrical controls that operate the air conditioner. It is located behind the front
access panel, in the lower left corner of the air conditioner.
a. Removal. Remove the junction box from the air conditioner as directed in the following procedure.
(1) Unscrew four panel fastener screws from the front access panel and remove the panel.
WARNING
Disconnect power from the air conditioner before performing maintenance work
on the electrical system. The voltages used can be lethal.
(2) Disconnect all electrical plugs from the receptacles on
the junction box (See 10,11,12,13, figure 4-3).
(3) Detach circuit breaker actuator as following:
(a) Loosen the screw in the core end fitting (14), and slide the fitting from core wire.
(b) Remove two screws and lock washers from the cable hold-down clamp (16), and detach the cable from
the actuator arm (15) and junction box.
(4) Remove four screws (7, figure 4-9) from the corners of
the control panel assembly, and stow the control
panel assembly out of the way.
(5) Remove six screws (7, figure 4-3) through the left-hand edge of
the casing to
the junction box mounting
flange. Remove two screws (8) and washers (9) from the lower right-hand mounting bracket. Remove the junction box
from the unit.
b. Disassembly. Disassemble the junction box in accordance with the following steps; however, disassemble only
to the extent necessary to repair or replace components.
(1) Unscrew four panel fastener screws (1, figure 4-3) and lift off cover assembly (A).
(2) Tag wires for identification, and disconnect from components.
(3) Remove electrical receptacles by
removing four screws and self-locking nuts from the corners of
each re-
ceptacle.
(4) Remove six screws (19) from circuit breaker (20) and cover (21). Slide cover over actuator arm (15), and
remove actuator arm from circuit breaker by removing tie-bolt from handle. Remove circuit breaker and cover from
junction box.
(5) Remove filter-rectifier assembly (22) from junction box by removing four screws and lock washers from in-
side the junction box.
(6) Remove transformer (23) and insulation (24) from top of
junction box by
removing four self-locking nuts from
(7) Remove panel (23, figure 4-10) from junction box by
removing four screws. Remove panel with electrical
components attached.
(8) Remove components from panel, if damaged or failed test requirements, by removing nuts or screws as
c. Inspection/Test. Visually inspect the junction box and its components for obvious damage, including evidence of
electrical short circuits or burnouts. Test components as directed in the following steps:
(1) Fuses.
Remove fuses (12, 13, figure 4-10) from fuse blocks, and test for continuity with an
ohmmeter or
continuity tester. Replace fuses that do not indicate continuity.
(2) Circuit Breaker. Turn the circuit breaker on, and check the continuity of
each line-load pair on
the three
main breaker units, and of points 3-5 on the auxiliary switch, using an ohmmeter or continuity tester. Continuity should
be indicated between each pair tested.
4-38