PS Magazine - TB 43-PS-629

PS, The Preventative Maintenance Monthly

ISSUE 629

APRIL 2005
PS Magazine - TB 43-PS-629 - Page 13 of 33
M249 Machine Gun…
Which
Side is
Up?
Dear Half-Mast,
The M249 machine gun's
TM 9-1005-201-10 on
Page 3-61 says to install
the transfer mechanism
with the headed end of the
vertical pin up. I have trou-
ble telling which is the
headed end. One side of
the mechanism has a pin
with an indent and the
opposite side has a
flat-head pin.
Which should go up?
V.B.
PS 629
APR 05
22
M68 Reflex Sight…
I
f the battery isn't installed correctly in your M16 rifle or M4 carbine's M68 reflex
sight, you can short circuit the sight. And that short circuits your own sighting.
So here's what you need to do when you install the battery:
•
Remove the battery cap by turning it counterclockwise.
•
Check that the rubber O-ring
is on the 6-pronged connection
post (some earlier versions may
not have the O-ring).
•
Eyeball the spring connector
for corrosion. Make sure the con-
nector sticks up slightly from the
foam pad. If you spot corrosion,
clean if off with a wire brush.
•
Check that the rubber O-ring is on the battery cap. It prevents corrosion.
Dear Mr. V.B.,
Put the transfer mechanism in the receiver
with the flat-head pin side up.
Side with
flat-head
pin goes
in facing
up
•
Insert the battery in the cen-
ter of the battery cap with the
positive end towards the cap.
Never use your finger to force
the battery into the battery com-
partment against the contacts.
Don't bend or move the prongs
for better battery contact. That
could lead to a short circuit.
•
Never bend, cut, or modify in any way the O-ring, foam pad, spring connector, 6-
pronged clip, or batter cap. That could ruin the M68.
•
Turn the battery cap clockwise until it's handtight. Don't force it tighter or you
could damage the sight.
•
Turn the rotary switch clockwise to make sure the red dot appears.
Time to get
you a new
battery!
That
wasn’t
the way to
install a battery! Now you’ve
short-circuited
me!
Here’s the
correct
way
to install the
battery in your
M68 optical
sight!
Spring
connector
corroded?
Rubber
O-ring in
place?
Positive end goes in first
Stop
Short Circuiting
Short
629.22-23(C)
2/25/05
1:35 PM
Page 1
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