TM 5-4520-253-13
Table 4-1. Intermediate Maintenance Troubleshooting – Continued
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Step 2. Test ventilating air motor capacitor. Pull
capacitor boot away from end of capacitor
(1). Tag and disconnect brown wire (2)
and two white wires (3 and 4). Set volt
ohmmeter on R x 100. Put one probe
against each capacitor terminal (5 and 6).
Meter should indicate infinity, Reverse
probes. Reading should jump to 15,000
ohms and immediately fall back to in-
finity, If meter fails to react as described,
capacitor is defective.
Step 3. Test
Replace defective capacitor (1).
Loosen screw (7) and pull capacitor
out of mounting bracket (8). Slide
new capacitor into mounting bracket,
tighten screw, and connect brown
wire (2) and two white wires (3 and
4) to capacitor.
Position boot over
end of capacitor.
ventilating air motor. Disconnect red wire (1) of motor (2) from red wire
(3) of PC board (4). Connect ac ammeter (5) in series with red wires (1 and
3). Turn HEATER-OFF-FAN switch to FAN. With motor (2) operating
under fan load, current draw shall not exceed 5.4 amperes. Check motor speed
with tachometer.
Motor speed should be 2950 rpm at 50 Hz and 3500 rpm at
60 Hz.
If current draw is too high or motor speed is low, and capacitor is good,
replace motor. No repair is authorized. Refer to REMOVE/lNSTALL
VENTILATING AIR MOTOR, page 4-53.
4-8
