PS Magazine - TB 43-PS-636
PS, The Preventative Maintenance Monthly
ISSUE 636
NOVEMBER 2005
Preventive Maintenance
Make sure you use the strain relief clamp to take the pressure off the RF cable
connection so that the full weight of the cable is not pulling down on the connector.
PM on the winch is a must.
Nothing
on the winch breaks more often than the
flange on the drum that anchors the end
of the wire rope. It breaks because you
work it and weaken it by bending it
back to insert the lug end of the rope.
Once the flange is bent back out of
position, it hits the winch housing with
each rotation of the winch. It’s not long
until the flange is gone.
Check your winch. If the flange is
gone, don’t use it. You need a new
winch. If the flange is bent back, care-
fully bend it back into place.
Before mounting the winch on the
mast, check the caphead bolts. Make
sure they’re not bent or loose. Check for
cracks. If you find bad bolts or cracks,
don’t use the mast.
The safety catch on the winch locks up the gear teeth and stops the antenna from
retracting. It does that, that is, if it is not frozen in place by rust. Lube the safety
catch each time you assemble the antenna and again before storage with silicone
grease, NSN 9150-01-197-7693.
Don’t overdo it. Just a little lube on your fingertips and rubbed on the catch
assembly will do nicely.
Never lube the catch after the antenna is erected.
You could accidentally
release the catch!
Check the full length of each hoisting rope for broken wire in any of the strands
or any other signs of serious wear. If there are broken strands or extensive wear,
replace the rope.
PS 636
NOV 05
42
The QEAM won’t go up and won’t
come down if the gearbox that raises and
lowers it fails. The gears in the box must
turn freely with little resistance.
One of the biggest problems on the
gearbox is with the
output shaft failing
to engage the drive screw.
Because the
rear of the shaft is not reinforced, the
shaft often falls back into the gearbox
and draws level with the flange. When
that happens, there is not enough shaft
left to fit into the drive screw groove. You
can crank the hand crank all you want,
but you’ll just be spinning the gears!
When this happens, you’ll need a new gearbox, but there is
a field expedient fix.
Unscrew the bottom of the gearbox and push the output shaft up until enough of it
is beyond the flange to engage the drive screw. Keep it in place by inserting wood,
paper or metal behind the shaft. This fix will make the cranking a harder task, but
the antenna will raise and lower.
When you have the bottom of
the gearbox off, you might notice
that the seal between the bottom
and the box has not done a very
good job. Chances are there is
water or signs of water in the
box. When you screw the bottom
of the box back in place, put a
line of silicone sealant, NSN
6850-00-880-7616, around the
mating area to keep the inside of
the box dry.
Check the top section of your mast for stress cracks. If you spot any, reinforce
that area with tape, NSN 5970-00-419-4291.
Add tape for support
Seal with
silicone
Do
gears
turn
freely?
Not
enough
shaft?
A weak
flange
soon
breaks
off
Is your
flange
weak?
Check the
full length
of the rope
636.42-43(C).qxd
9/30/05
9:36 AM
Page 1
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