TM9-4120-401-14
FAULT INDICATOR, LIGHT EMITTING DIODE (DS1, DS2, DS3, AND DS4).
This task covers:
a. Inspect
b. Test
c. Replace
INITIAL SETUP
Equipment Conditions:
Remove control panel (para 4-25).
Refrigeration Unit Service Tool Kit
Appendix B, item 1
Crimping Tool Kit
Appendix B, item 2
Materials/Parts
Light Emitting Diode
Lock Washers (4)
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 missing terminals. Replace if damaged.
b. Test.
(1) Using a multimeter set to test diodes, connect red lead to connector (7) pin number 2 and black lead in
turn to pin numbers 4, 9, 10, and 11 (DS1, DS2, DS3, and DS4) (figure 4-6). 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.
4-74
