Rick, I had a similar problem with an LM-470. It turned out that the
solution was a rusted shaft between the motor and the large pulley. A
squirt of oil onto the shaft and toward the portion of the shaft inside
the motor did the trick. YMMV.
73, Joe
K2XX
Rick Stealey <mailto:rstealey@hotmail.com>
Friday, June 20, 2014 12:10 PM
K2XT, Rick here. I've recently been having trouble getting my tower to
extend easily. It is a US Tower TX472 with the motor drive. Symptom
when I first experienced the problem last fall was very sluggish
starting. I'd give it a few seconds in each direction and then it
would get going.
So now that I am in the midst of extensive maintenance (new winch
cables, and some antenna work) I notice that the motor stalls out
completely, and blows it's circuit breaker or thermal cutout, whatever
it is, after 2-3 seconds. And of course there is no upward movement of
the sections. I replaced the starter capacitor. Same thing. I removed
the motor and it runs fine with no load.
Ok, so my next theory is a pulley is jammed, and that's where I seek
some advice. I tried turning the "steering wheel" pulley by hand while
the motor is off. That is the approximately 8 inch pulley that is
driven by the belt from the motor. In the direction that should raise
the tower sections it gets so tight that there is no way whatsoever a
human could turn it more, and my gut feeling tells me there is also no
way I should expect the motor to turn it. So, do I have a bad pulley
on the tower sections, and how to know if a pulley is bad?
So, this morning, with the tower horizontal, I loosened the winch
cable and removed a bottom pulley. A 3.5 inch dia one. I can hold the
bushing and try to spin it. It turns and I can feel the bearings
inside but trying to get it to spin and it only goes maybe a quarter
turn. The feel of the bearings is sort of uneven. Could that bit of
friction be causing the trouble? Of course I may find another pulley
(hopefully) that is completely frozen, and that would solve my
problems. Any opinions? Any first hand experience with such a
situation? I put some motor oil on the bearings, no change. What about
soaking the pulley in solvent, then oiling?
Thanks for any input.
Rick K2XT
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