TM 5-4940-228-14
Table 5-1. Direct and General Support Troubleshooting.
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
1. Pressure cup will not pressurize properly.
Step 1.
Check gasket in lid for cracks, tears, damage or paint build up.
Step 2.
Remove pressure tube and inspect for clogs, bends or damage.
Step 3.
Inspect diaphragm for cleanliness on lid side; a stuck
diaphragm will not allow air into cup.
Disassemble pressure cup, inspect all parts,
clean thoroughly and reassemble.
2. Air motor on pressure tank will not turn.
Step 1.
Check for dirt build up inside body by flushing with a petroleum
based solvent (para 8-2).
Disassemble and replace damaged parts.
3. Air motor turns, but has little power.
Step 1.
Check felt pads in muffler for contamination. Replace
pads if clogged.
Step 2.
Check for air leaks between body and end plates. Tighten
screws if leaks detected.
Replace gasket if problem is not resolved.
Step 3. Remove one end plate and check vanes for excessive wear.
Replace if worn. Disassemble air motor (para 8-3).
4. Regulator pressure rises gradually after adjusting.
S t e p 1 .
Remove bottom plug, spring and valve. Check for dirt
or foreign matter.
Clean valve and inside body with a clean cloth.
5. Regulator pressure drops when in use.
Step 1.
Check for cracked or damaged diaphragm.
Replace diaphragm (Fig. 6-1).
6. Compressor does not unload.
Step 1.
Check pilot valve line for cracks, dents, or other damage.
5-2
