I sent a variation on this post to Jerry at SteppIR this afternoon:
I've been thinking about the problem, too, and I've come to the conclusion
that the power supply test won't reveal much -- only whether the fault is
marginal or not. Not much else.
Even trying the controller out at the tower isn't conclusive because it
could be a marginal motor condition interacting with the longish cable. If
that's the problem, it'll look like it works at the base of the tower. So
the cable will be yanked out of the conduit and another one will be pulled,
but the result will be the same. The owner won't even know whether it's a
marginal motor interacting with a long cable, or whether he damaged both
cable runs during the pulls!
A much better test is to try a separate run of controller cable temporarily
laid along the ground to the tower. The nice thing about this is that AC
doesn't have to be brought to the tower. But it does mean the cable must be
cut and spliced at the tower, and then the junction must be weatherproofed
when testing is completed. I see no way to avoid this. I recommend the Avaya
telco connectors suggested by K7LXC for that job (plus a weatherproof
junction box or vapor wrap and electrical tape.)
If the temporary run works, then it's certain that the cable in the conduit
is bad. He can replace it with the temporary run, and if that doesn't work
it'll be evident that both cables were damaged during the pull.
Unfortunately, if the temporary cable doesn't work, the owner will not know
if there's a marginal fault somewhere in the cable run up the tower or in
one of the motors. He could try replacing the cable run up the tower with
some of the temporary run. If that doesn't work, then I see no alternative
but to take the antenna down and try substituting spare passive and driven
EHUs to pinpoint the motor with the fault.
73, Dick WC1M
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