TM
11-6125-240-12
b. Remove grease, fungus, and ground-in dirt from
Table 3-2. Periodic PMCS
Total time required: 0.3
the exterior surfaces with a clean cloth dampened (not
wet) with trichloroethane. Wipe dry with a clean, dry,
Sequence
Work
Item To Be Inspected
lint-free cloth.
time
number
Procedure
(M/H)
c. Remove dust or dirt from the ac power connector
0.1
1
PUBLICATIONS:
and associated plug with a soft-bristle brush.
Check to see that all publications perti-
nent to this equipment are on hand,
3-7. Troubleshooting
complete, and usable. Check DA Pam
310-4 for recent changes to publications.
The troubleshooting procedures in table 3-3 are based
2
MODIFICATIONS:
upon symptoms noted while the inverter is in operation.
Check DA Pam 310-7 to see that all urgent
Any malfunction observed that is not included in the
MWO's have been applied, and that all
normal MWO's have been scheduled.
table should be referred to higher category mainte-
0.1
3
INSTALLATION:
nance.
Check to see that the inverter is prop-
erly secured with safety wire attached.
3-8. Maintenance
4
SLIPRINGS:
Remove the ac end cover and inspect the
Periodic inspection (every 200 flying hours) of the ac
sliprings for excessive wear and pitting,
contact brushes is the only maintenance performed at
0.1
5
AC CONTACT BRUSHES:
the organizational level. This operation may be per-
When accessible, remove the ac contact
brushes as in paragraph 3-8 and inspect
formed in the aircraft if the inverter can be reached
for wear cracks, chips, and broken
easily. Otherwise, remove the inverter from the aircraft
flexible wire. Check brush holders and
as in paragraph 2-3.
springs for cleanliness and proper
tension. Refer inverter to Direct
3-9. Adjustment of Output Voltage.
Support maintenance for replacement.
The increase volts adjustment (fig. 1-2) is adjusted to
3-6. Cleaning
provide 115 volts ac output. Follow the procedure
All exterior surfaces of the inverter should be free of
given below.
dirt, grease, and fungus. Perform the following proce-
a. Turn on the necessary aircraft switches to start the
dures as specified in the preventive maintenance checks
inverter. Set the multimeter range to 1000 AC VOLTS
and services table 3-1.
and connect its test leads to the test point jacks on the
a. Remove moisture and loose dirt with a clean soft
front of the regulator housing. Note output voltage
cloth.
reading.
WARNING
b. Loosen the locknut on the increase volts adjust-
The fumes of trichloroethane are toxic, Pro-
ment resistor. Using a screwdriver, turn the voltage ad-
vide thorough ventilation whenever used.
justment shaft clockwise to increase and counterclock-
wise to decrease output voltage, until the multimeter
DO NOT USE NEAR AN OPEN FLAME.
Trichloroethane is not flammable, but expo-
indicates 115V ac.
c. After adjustment, tighten the locknut on the ad-
sure of the fumes to an open flame or hot
metal surface forms highly toxic phosgene
justment shaft. Disconnect the multimeter leads, and
gas.
turn off the aircraft power.
Table 3-3. Troubleshooting
Corrective action
Malfunction
Possible cause
Inverter vibrates . . . . . . . . . . . . . . . . . . .
a. Loose or missing hard-
a. Tighten or replace
ware.
hardware.
b. Inverter improperly
b. See that mounting
seated.
surface is clean
and free of foreign
objects. If
trouble is not cor-
rected higher cate-
gory maintenance is
required.
Inverter fails to start . . . . . . . . . . . . . . . . a. Loose or blown fuses
a. Check and replace or
reset as required.
or open circuit
breaker in dc line.
b. Short circuit in dc line . . . . . . . . . . . . . . . . . . . b. Check aircraft line fuses
or circuit breakers. If
blown, inspect wiring
between fuses or circuit
3-2
