Mr. Towertalk, Steve K7LXC, remembers similar problems I had with my
HDX-672. It was intermittent, sometimes failing to go up, sometimes
down, sometimes either direction. It failed frequently even though it
worked more times than it failed. I tried swapping relays and various
time delay settings to no avail. I talked to UST's electrical guy (a
contractor they are loathe to call in without serious stress) who
explained my control box to me. There are two pairs of relays in the
box. The mainly black ones are the primary motor control relays, one up
and one down. There is a little plastic button sticking out the case of
these relays that lets you move the contacts manually, bypassing almost
all other circuitry. You must be careful not to run the tower too far up
or down with these as the limit switches are out of the circuit. In my
case, the buttons would work every time, even when the tower was failing
to move both before and after the bypass button test. I had ruled out
the limit switches with an ohmmeter, so I concluded that both time delay
relays (the white ones with a setting knob) were flakey. Yes, I
understood how unlikely that seemed but I reported the circumstantial
evidence to UST. They said they didn't know of any systematic problems
with these relays but sent me two replacements right away. From the day
they arrived (early November?), the system has not failed. That is, the
original equipment is now working and the new relays have not been
installed. Go figure.
GL & 73,
/Rick N6XI
kg6i@att.net wrote:
>I was advised by Steve K7LXI ?? to ask for your advise on my problem with my
>TX-472MDP tower. It will not engage the motor to move UP, but will work fine
>DOWN. About a year ago, it did the same, and in frustration, I gave the
>control box on the tower a good smack with my hand, and it worked again.
>Smacking doens't work now. I took the cover off, inspected everything, all
>looked fine. I even pulled the two large time-delay relays out of their
>sockets and re-seated them, but still no-go. Any ideas I should try?
>Thanks, John
>
>
>
>
--
Richard M. Tavan
20297 Hickory Hill Way
Saratoga, CA 95070
n6xi@arrl.net
rtavan@alum.mit.edu
tavan@tibco.com
408-867-5797 Home
408-867-5791 FAX
650-846-5214 Office/Voice Mail
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