TM 9-4120-378-14
4.29 CAPACITORS. - continued
Location/Item
Action
Remarks
Test
b.
Ohmmeter needle should move rapidly toward
- Continued
top of the scale; then, slowly return toward zero if
the capacitor is good.
c.
If needle moves to top of scale and remains
there, the capacitor is internally short-circuited; if
the needle does not move, the capacitor contains
an open circuit.
d.
Replace capacitors with short/open circuits.
If the capacitors have a metal case, check also
e.
for shorts to case.
f.
There will be no deflection of the ohmmeter
needle if the capacitor is good. If the needle
does deflect, replace the capacitor.
Check compressor start capacitor resistor with
g.
ohmmeter. Nominal value 15 kiloohms plus/mi-
nus 20% (Range 12,000-18,000 ohms). If defec-
tive, discard and replace. Resolder serviceable
start capacitor terminals,
NOTE
Compressor start capacitor (C5) is installed on all
units. When compressor (97403) 13208E4120-10 is
used this capacitor is not connected. Wires from ca-
pacitor (C5) are connected to dummy terminal board
TB4 on units with 13208E4120-10 compressors. See
wiring diagram fig. FO-3.
Compressor
Run Capacitor
(10)
Test
Test capacitor (10) for internal leakage and short
or open circuits by using an ohmmeter set at
maximum resistance.
Check for internal condition by placing the test
leads of an ohmmeter on the terminal of the ca-
pacitor. Place positive (+) lead to positive termi-
nal and negative (-) lead to negative terminal.
The ohmmeter needle should move rapidly to-
ward top of scale; then slowly return toward zero
if capacitor is good. If needle moves to top of
scale and remains there, the capacitor is internal-
ly short-circuited; if the needle does not move,
the capacitor contains an open circuit. Replace
capacitor indicating short or open circuits.
4-74
