PS Magazine - TB 43-PS-602

PS, The Preventative Maintenance Monthly

ISSUE 602

JANUARY 2003
PS Magazine - TB 43-PS-602 - Page 22 of 30
PS 602
JAN 03
47
IN SHAPE
IN SHAPE
Thanks for the antenna
tips, Mr. Uber. We’re all
for any ideas that extend
the life of equipment
through preventive
maintenance. Operators,
if you still have the
AS-3900 antenna
supporting your vehicle-
installed SINCGARS,
make a PMCS plan of
your own in order to keep
the antenna working.
Also, if you’re missing
those screws, take Mr.
Uber’s recommendation
and order them today.
PS 602
JAN 03
46
SINCGARS…
KEEP THE AS-3900
KEEP THE AS-3900
Dear Editor,
Many of our vehicle-installed SINCGARS still have the AS-3900 anten-
na, NSN 5985-01-189-7925, and not the replacement AS-3900A, NSN
The AS-3900 is no longer supported with preventive maintenance
instructions or repair parts. In fact, when it goes bad, you turn it in for the
Alpha model.
However, I see no reason why the AS-3900 can’t be maintained and
given a longer life. Just some basic PMCS will keep the antenna in shape and
delay replacement costs. Here’s what I recommend:
The main problem is water get-
ting into the matching unit. I have
found cup-fulls of water in match-
ing units. The matching unit should
be regularly checked for cracks in
the upper housing. The upper
housing should be kept clean and
small cracks should be sealed with
RTV.
Matching units need to be reg-
ularly drained through the hole in
the bottom of the matching unit
by removing the screw.
Another problem is missing screws! A
missing screw lets moisture into the housing.
The original screw
is no longer available,
but I’ve found a sub-
stitute that works.
Order stainless steel
screw, NSN 5305-
00-054-6666.
Put a sealing washer,
NSN
5330-00-
448-1018, on with
the screw. Finish the
job with a dab of sili-
cone grease, NSN
6850-00-880-
7616,
on
the
threads.
Jim Uber
AMSA #76
Niagra Falls, NY
From the desk
of the
Editor
Replace missing
screw with this one
Remove
screw
and
drain
tell me about
it! We’re not
even supported
with repair
parts anymore!
you might
be getting
older…
1-2-3-4!
2-2-3-4!
we’re
old!
why do we
have to go
through these
exercises?
…but you’ll
still work
as long as
we keep you
in shape!
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