TM 9-4120-403-14
Inspection
(1) Loosen setscrews in both knobs and remove knobs.
(2) Remove four screws and locknuts that secure rear panel.
(3) Pull rear panel away from box as far as harness will allow.
(4) While holding rear of mode selector switch, remove nut, lockwasher and switch.
(5) Check switch to see that all leads are properly connected. (See wiring diagram, fig. 4-43).
(6) Repair or replace all loose or broken leads.
(7) Check that switch terminals are not loose or broken.
(8) Check switch for evidence of overheating or other visible damage.
(9) Replace switch if damaged.
Test
(1) Using multimeter and switch position chart shown on figure 4-21, check continuity at contacts indicated. With
switch position closed, continuity should be indicated. With switch position open no continuity should be indicated.
Check between each set of contacts and at each switch position.
(2) Replace switch if it fails above test.
4-58