[TowerTalk] Failed Limit Switches on Crank-up Tower

[Dick Flanagan]

>Today I replaced the limit switches on my 72 foot motorized crank-up
>tower from US Tower. The lower one failed first, fortunately.  (The
>limit switches automatically turn the tower motor off when the tower
>telescopes to its limits - up or down). When I opened up them up, I
>found that they were very badly corroded   - to the extent of what you
>might see if a battery had leaked inside them. I was surprised to see
>the extent of corrosion because I have owned the tower for less than
>three years.
>
>Has anyone found a way to get a longer lifespan out of these switches?
>They cost $130 each to replace.

I had the exact same problem with one of my limit switches, but Bruce
at US Tower was nice enough to replace it under warranty.

What had happened in my case was the tower had lain on its side over a
rainy winter before I could install it.  With the tower on its side,
one of the switches had its control cable (and the hold through which
it enters the switch) pointing skyward.  Rain water ran down the cable,
through the hole and completely corroded the inside of the switch.

I have added an internal inspection of both limit switches to my annual
inspection routine and have taken care to waterproof where the cable
enters the switchs.

73, Dick

--
Dick Flanagan W6OLD CFII Minden, Nevada DM09db (South of Reno)
Visit http://www.qsl.net/cvrc/



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