Erik,
These rotors use DC to actuate the drive motor. The drive voltage and
position indication signal (also DC) both pass through the rotor cable and
all its connectors. Any leakage current from the drive voltage appearing on
the signal line can cause an erroneous position signal to be sent to the
control box whenever the drive is commanded. The needle will swing
erroneously until the drive voltage is removed, then settle back to indicate
the correct position. It will swing in either direction, depending on
whether the rotor is commanded clockwise or counterclockwise (drive polarity
is reversed).
When this happened to my 800SDX, I measured resistance at the lower end of
the rotor cable and found erratic and intermittent leakage between the drive
pins and the indicator pins and ground. As I recall the schematic, there
should be no continuity between the drive lines and ground. I then checked
the connector at the rotor. There was a lot of insect debris moistened by
rain, condensation or whatever inside the cable connector. Evidently (and
not surprisingly), the flexible connector boot does a poor job of
weatherproofing. Anyway, when I cleaned the mess out of the connector (both
front end and backshell), the resistance readings returned to normal, and
the system behaved correctly when reconnected to the control box. This is
consistent with the fact that the erratic behavior always followed a
rainstorm and recovered after a few warm, sunny days! I filled the front end
and backshell with non-conductive grease and taped the connection with
Scotch 88. That was two years ago...it took a couple of trips up to the
rotor, but the problem has not returned. I was very happy to avoid removing
the rotor for servicing.
I can also believe that a lightning pulse could clear the short too, for a
while, until something tries to again use the connector as a home.
Try this before you undertake a rotor removal!
Good Luck!
Chuck, N4NM
----- Original Message -----
From: "Erik Jakobsen" <erik@urbakken.dk>
To: <towertalk@contesting.com>
Sent: Monday, December 02, 2002 2:54 PM
Subject: Re: [Towertalk] RE: Yaesu G1000SDX
> On Mon, 2 Dec 2002 15:36:29 -0500
> "Rudy Marcelletti, K8SWD" <rudym@net-link.net> wrote:
>
> > Erik: You take a lightning hit? I don't computer control my G1000SDX,
but you describe what mine did for a while after a close strike, or direct
hit--I don't know which. The needle would spin around uncontrollably and
sometimes point in the right direction, sometimes not. When I would look
outside, the antenna was aiming correctly where I had the preset pointing,
but the needle would spin wildly, but would eventually stop in the vacinity
where I was pointed. Well, this summer I took another hit--direct I think.
It wiped out about $3,500.00 of on non-ham stuff in the house, but only 2
ham power supplies. My rotor is now FIXED! No explanation for it other
than something up top was loose as my controller was disconnected at the
time of the storm, and lightning fixed it!
>
> Hi Rudy.
>
> So far I do not know about a lightning attack here :-).
>
> I'm not quite sure if the antenna is being rotated with the same speed as
the needle does. But of course I'll have a look at it.
> Will give it a try with the presets. Once I was out it seemed that the
antenna did rotate according to the needle, but I'm not sure.
>
> Well I'll be back when I have done the test.
>
> Tnx for your kind replying.
>
> > Rudy Marcelletti, K8SWD
> >
> >
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> > _______________________________________________
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>
> --
> Med venlig hilsen - Best regards.
> Erik Jakobsen - erik@urbakken.dk
> Registered Linux user #114875 - http://counter.li.org
>
> _______________________________________________
> AN Wireless Self Supporting Towers at discounted prices,
> See http://www.mscomputer.com
>
> Wireless Weather Stations now $349.95. Call Toll Free,
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