PS Magazine - TB 43-PS-589

PS, The Preventative Maintenance Monthly

ISSUE 589

DECEMBER 2001
PS Magazine - TB 43-PS-589 - Page 26 of 32
PS 589
A Better, Cheaper Tube
K
eeping an NSN list of hard-to-find parts is
usually a good idea. But a good idea can some-
times lead to a bad result. Here’s an example:
For the AN/PVS-7B night vision goggles
(NVG), you probably have NSN 5855-01-328-
3540 listed for the image intensifier tube. On
your list for the AN/PVS-7D, you probably have
NSN 5855-01-422-4720 listed.
But these two tubes are interchangeable. And,
not only is the 7D a better tube, it’s cheaper! If
you order it to put on your 7B’s, you’ll save your
unit $400 on each tube.
If you check the FED LOG-AMDF, you’ll see
that the 7B NSN is in a "Use Until Exhausted"
posture. Then you are to order the 7D tube. But
here’s the catch–-the 7B NSN has already been
dropped from TM 11-5855-262-23&P-2! Only
the 7D tube is listed. That means you can order
it now for your 7Bs as well as your 7Ds.
PS 589
DEC 01
48
A
night crawl through muck and mud can make a thorough cleaning job a must for
your night vision goggles, AN/PVS-7B or -7D.
TM 11-5855-262-10-2 gives you the good word on careful cleaning, but there is
an area on the face of the goggles that the TM doesn’t tell you
how
to clean. That
area is where the high light detector and infrared source are located.
These two indented sensors catch and hold
dirt like a spider’s web catches a fly. They
need to be cleaned, but here is where our
story has a twist. The problem is not that you
aren’t cleaning them. The problem is you’re
cleaning them too hard!
The only thing holding these sensors in
place is a rubber seal. When you’re cleaning
in the indented areas, you’re pushing the sen-
sors out of their seals and into the goggle
body. That makes your NVG NMC!
So never use a cleaning swab, stick or other
pointed device to clean this area. It’s just too
easy to push the sensors out of their seal.
Instead, clean away loose
dirt with lens brush, NSN
stubborn dirt, use your finger
covered with water-dampened
lens tissue, NSN 6640-00-
240-5851, and lightly clean
the area. Start on the surface
of the sensor and pull toward
you instead of pushing in.
If a sensor does pop out of
its seal and into the goggle
body, turn the goggles in.
Go easy on high-light detector
and infrared sensors
7D is cheaper
AN/PVS-7B, AN/PVS-7D.
..
7B
7D
I hope the
next
soldier
forgets
to clean his
goggles
too!
7B
7D
I’m
better
and
cheaper!
589. 48-49 (C)
10/25/01
4:58 PM
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