TM 9-4120-370-14
TO 35E9-229-1
TABLE 4-2. TROUBLESHOOTING (cont.)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Disconnect input power before performing internal electrical troubleshooting.
Voltages used can be deadly.
Test relay. (See para 4-55). Replace relay if defective.
Step 2. Check operation of conditioned air (evaporator) fan motors (B3 and 64).
Test motors. (See para 4-60.) Contact direct support maintenance if motors are defective.
Step 3. Check operation of mode selector switch (S).
Test switch. (See para 4-40.) Replace switch if defective.
7. EXCESSIVE NOlSE WHEN COMPRESSOR STARTS.
If a knocking or hammering sound is heard when compressor starts, turn mode
selector switch to OFF, immediately. Such noise is usually caused by liquid re-
frigerant in compressor, which can seriously damage or destroy compressor.
Contact direct support maintenance.
Disconnect input power before performing internal electrical troubleshooting.
Voltages used can be deadly.
Step 1. Check for a defective compressor.
(Contact direct support maintenance.)
8. EXCESSIVELY NOISY OPERATlON.
Step 1. Isolate source of noise as near as possible, both by ear and touch.
Listen and feel at both front and back of cabinet.
Step 2. Check fans for looseness or damage, and for rotational clearance.
Tighten loose fans, adjust for rotational clearance, or replace if damaged.
Step 3. Check all internal components for looseness, vibration, and security.
Tighten, adjust, and secure as necessary.
4-40