TM 55-4920-404-30&P
screw holding the weatherproof cover plate and re-
place. If the outlet needs replacement, de-energize
All repairs/replacement to the ECU
the shelter and remove the power inlet box cover as
cable/connector should be performed
previously described. Remove screws and nuts hold-
with the 30 amp circuit breaker
ing the outlet to the panel. Remove the wires from
turned off.
the connector and discard the damaged connector.
(2) The power connector may be repaired by
Install wires on the new connector, install mount-
resoldering broken wires. Minor damage to the
ing hardware, and weatherproof cover plate. Rein-
cable jacket may be repaired by wrapping with plas-
stall power box cover and energize the shelter.
tic electricians tape. To replace the cable and con-
(5) Repairs to the power inlet panel is limited
nector, remove the box cover plate and disconnect
to replacing loose rivets and repairing dents and
the cable wires. Loosen the cable clamp and remove
minor sheet metal punctures.
cable. Install new cable and tighten clamp. Connect
d. Circuit Breaker Panel.
cable wires to shelter wiring and solder connector to
free end of cable in accordance with shelter wiring
(1) In the unlikely event the entire circuit
diagram in drawing 4920-EG-056, figure D-1, test
breaker panel requires replacement due to exten-
connector with an ohmeter for shorts between con-
sive damage to the case or electrical damage to the
tacts.
bus bars, a new panel maybe installed. De-energize
the shelter and remove the power cable from the
CAUTION
power inlet connector. Use a trouble light to illu-
Be sure that power is off before test-
minate the shelter. Remove the cover and discon-
ing any circuit with an ohmeter.
nect all wires.
NOTE
for proper phase connections.
Put a masking tape label on each wire
NOTE
as it is disconnected to aid in proper
re-assembly.
ECUs have 3 phase motors which will
malfunction if proper phase con-
(2) Loosen and remove all conduit connector
nections are not maintained.
retaining nuts. Remove four screws holding the
panel to the backing plate. Install new panel using
g. Inside Electrical Outlets. Turn off circuit
the sheet metal screws removed from the old panel
breaker supplying power to the inside electrical out-
or new ones by snapping them into place in the
lets. Remove cover plate, remove screws securing
same position as on the old panel. Connect wires as
receptacle to box and remove wires from receptacle.
previously labeled and refer to the shelter wiring
Install new receptacle connecting wires the same as
diagram in drawing 4920-EG-056, figure D-1, Ap-
on the the old one. Install new receptacle con-
pendix D. Replace breaker panel cover and re-ener-
necting wires the same as on the old one. Install
gize shelter. Check all circuits for proper operation.
mounting screws and cover plate. Turn on circuit
breaker and check circuit for proper operation.
e. Circuit Breakers. Circuit breakers are re-
placed when they become physically damaged or
fail electrically to operate properly. De-energize
All electrical repairs or replacements
shelter and remove shelter power cable. Illuminate
should be performed with the power
the shelter with a trouble light. Remove circuit
off by an aircraft electrician or other
breaker panel cover. Disconnect the wire attached
qualified person.
to the circuit breaker and remove the breaker by
pulling outward and to the side. Snap in a proper
h. Power Distribution Panel.
size replacement, reconnect the wire and reinstall
(1) The power distribution panel should be re-
panel cover. Re-energize the shelter and check cir-
placed as a unit when damaged extensively.
cuit for proper operation.
(2) The power cable may be replaced by re-
f. ECU Power Cable.
moving the cover of the weatherproof junction box
(1) Check cable for signs of fraying, cracks,
and labeling the phase connections of the No. 6
etc.
gauge wires from the cable wires. Save the wire tap
3-3
