TM 10-6640-215-13 Table 2-1.  Operator Preventive Maintenance Checks and Services Item Interval Item To Check Procedure Not Fully Mission No. Service Capable If: 37 During Purge Intake a.  Inspect door microswitches to Microswitches do not op- Doors be sure they activate properly erate properly. when door is closed, and deacti- vate when door is opened. b.  Inspect filters for obstructions Clogged, dirty, defective and security. filter. 38 During Mechanical Inspect dampers and motors for Motor does not operate. Room, ECU In- operation. takes 39 During Air Compressor a.  Listen for rattles, knocks, Vibration or unusual squeaks, or hums that may indi- noise occurs. cate trouble in air compressor or motor. b.  Observe motor for indication Motor overheats. of overheating and smoke. c.  Drain moisture tray as re- quired during operation. 40 During Air Tank and Sys- a.  Check for loose mounting Missing mounting bolts. tem Piping bolts. b.  Inspect for leaks, leaky Air leaks or defective valves, or inoperative valves. valves. c.  Drain air tank as required during operation. 41 During Vacuum Pump a.  Listen for rattles, knocks, Vibration or unusual squeaks, or hums that may indi- noise occurs. cate trouble in air compressor or motor. b.  Observe motor for indication Motor overheats. of overheating and smoke. c.  Observe drive belts for Drive belts are loose or cracks, slippage, or binding cracked. caused by excessive looseness or tightness of belt.  Proper drive- belt deflection should be 3/4 in- ches under moderate thumb pressure. 2-36