TM 5-4220-226-14&P
4-24. Helmet Communications Maintenance - continued.
b. Inspection
(1) Inspect communications components for cracked, frayed, or broken wires.
(2) Inspect for torn mylar diaphragms in the microphone and earphones.
c. Repair
Repair is limited to the replacement of damaged parts.
d. Installation
(1) Insert microphone (5) in the oral-nasal mask by feeding the wires from the interior of the mask
through the small hole in the microphone pocket.
(2) Install earphones (3) into the earphone retainers (4) attached to the helmet shell. Be sure the
earphone with the shortest wire is installed in the retainer on the side block assembly side of the
helmet.
(3) Connect microphone wires (1) and earphone wires (2) to the communications posts.
(4) Install helmet liner (para 4-23).
4-25. Umbilical Maintenance.
This task covers:
a.
Removal
b.
Installation
INITIAL SETUP
Tools Required
Tool Kit, General Mechanic's (item 4, appx B)
a. Removal
(1) Disconnect pneumofathometer hose (1), if used.
(2) Disconnect communications cable (2) from communications whip (3).
(3) Disconnect air hose (4) from the helmet adapter hose (5).
4-32
