TM 9-4120-402-14
4-30. MODE SELECTOR ROTARY SWITCH (S1). -continued
NOTE
FOLLOW-ON MAINTENANCE:
Connect power at power source.
4-31. FAULT INDICATOR, LIGHT EMITTING DIODE (DS1, DS2, DS3, AND DS4).
This task covers:
a. Inspect
b. Test
c. Replace
INITIAL SETUP
Tools
Equipment Conditions:
Refrigeration Unit Service Tool Kit
CAUTION
Materials/Parts
Use disconnect switch (NOT POWER
CABLE) to disconnect power to unit.
Damage to cable connector pins will
result if cable is used.
Lock Washers (4)
Disconnect power at power source.
a. Inspect.
(1) Remove four sets of screws (1), lock washers (2), and flat washers (3) securing control panel (4) to control
box (5).
(2) Carefully pull control panel (4) away from control box (5) as far as harness will allow.
(3) Check light emitting diodes (6) for loose or broken wire leads. Replace if damaged.
b. Test.
(1) Using a multimeter set to test diodes, connect red lead to connector P6 pin number 2 and black lead in turn
to pins number 4, 9, 10, and 11 (DS1, DS2, DS3, and DS4). The multimeter should indicate between 1 and
2 volt drop on each pin
(2) Reverse the leads from step (1) above and repeat check. The multimeter should give no indication on any
pin.
(3) Replace any light emitting diode (6) that tests defective.
4-98