[TowerTalk] Tic-Ring Pot
Fred Hopengarten
k1vr@juno.com
Tue, 29 Sep 1998 18:03:50 EDT
From:
Fred Hopengarten K1VR 781/259-0088
Six Willarch Road
Lincoln, MA 01773-5105
permanent e-mail address: fhopengarten@mba1972.hbs.edu
Summary I collected of remarks on the TIC Ring potentiometer follows the
question below.
On Tue, 29 Sep 1998 09:21:29 -0500 "Effinger SH (Sam) at MSXSOPC"
<SE060676@MSXSOPC.shell.com> writes:
>
>I must be doing something wrong...I replaced the pot in my 1032 tic ring
>less than 3 months ago and it's bad again..used the new Bourns pot from
>Tic-ring so it's not the old model....
>
>we haven't had any storm or any reason to think it was hit by
>lightning..
>
>I plan to put MOV's and .01 caps on all the leads plus ferrite
>beads...any other ideas..
>
>The only thing I can think of would be...I have the cable on a Jones
plug so
>I can disconnect it during storms. Maybe dis-connecting and
re-connecting
>with the power on caused a problem...
>
>the plug will only connect one way...
>
>any ideas ??? or just buy a handful of pots and install snaps for quick
>removal ??...I like this rotor when it works...
>thanks for any info on the Tic-ring and I am not bashing
>Tic-ring...they are
>great and I plan to put up at least 2 more..but having them rotate
>would be a great help...ha ..
>Sam K9SD
From: John Brosnahan <broz@csn.net>
Date: 28 Sep 1997
Subject: [TowerTalk] FOLLOWUP--TIC Ring intermittent
Wanted to thank everyone for their input and provide some feedback on
the TIC Ring pot failure. The borrowed motor/pot assembly works fine
and the failed unit has been disassembled for diagnosis. The failed
unit had only been up for a week or so with very limited use--mostly
just the initial testing and it worked flawlessly until the failure.
The post mortem appears to show now sign of mechanical distress on the
pot that would be associated with going past a stop. The back end
fixed-connection to the resistence winding just appears to have failed
open. There is a miniscule connection from the terminal post to the
winding and that had opened up. Only obvious candidates for the
failure mode are 1) defective pot design 2) defective pot manufacture
3) overheating from soldering the wire on the terminal. But the exact
cause appears to be impossible to determine.
Whatever it is that happens according to the bumper stickers seems to
have happened here!
Again, thanks for the input. It appears that this problem is not
widespread. Will check with the factory about their experiences later
this week and will consider replacing the pot with an equivalent unit
from another manufacturer such as Bournes.
John W0UN
===================
From: k3lr <k3lr@frogger.lm.com>
Date: 1 Oct 1997
Subject: [TowerTalk] TIC Problems Buzz
This is for Billy AA4NU and others who have had this problem. I know I
have! If the TIC control box buzzes when you want to rotate, the
problem is the pot at the rotor end. Take wires 3, 4 and 5 off and put
a 500 ohm pot in its place at the control box. This will allow you to
move the rotor. It could be just some dirt, but as W0UN pointed out,
the pots that TIC uses isn't the best. I know it is not meant to be
used outside. There is a real condensation problem. I replace all pots
at the rotor end every 2 years as a prevention against what will
happen in the middle of a contest. As John pointed out, the pots are
available from Digi-Key.
If anyone figures out a better 2 watt, 10 turn pot for the rotor, I
sure would like to hear about it.
Tim K3LR
===================
From: John Brosnahan <broz@csn.net>
Date: 1 Oct 1997
Subject: Re: [TowerTalk] TIC Problems Buzz
I called TIC yesterday (1-800-TIC-RING) and we played phone tag today
but they left a message saying that they had gone to a Bourns pot and
found it to be more reliable and would send me one out at no charge.
(No model number in the phone message.)
Will be interesting to see how the Bourns unit holds up--looks like
the problem may be the side force from the springiness of the sheet
metal that is used to provide a constant pressure on the (fine-
toothed) gears. I don't think the Clarostat is very happy with the
amount of side preload.
John W0UN
===================
From: W9JA Paul Hellenberg <w9ja@contesting.com>
Date: 02 Oct 1997
Subject: Re: [TowerTalk] TIC Problems Buzz
I bought 5 of the New pots for TIC to fix lightening damage and for
some stock.
Paul W9JA
===================
From: tgstewart@pepco.com
Date: 2 Oct 1997
Subject: Re: [TowerTalk] TIC Problems Buzz
There have been several different versions of motors put out, so I'm
probably not familiar with the one you are running. However, on my
1022B's when I did some work on the motors, I noticed the great amount
of side load on the pots. By working the holes out a little on the
bracket, I managed to cut that down to where it is just enough to
provide a comfortable mesh between the gears. So far I've had some
jumping of the indicator, but no out and out failures.
Ty K3MM
===========================
From: John Brosnahan <broz@csn.net>
Date: 7 Oct 1997
Subject: [TowerTalk] FYI: TIC replacement pot
Just received the new pot to replace the Clarostat pot in the TIC
General 1022 ring rotator. It is a Bourns 3590S-4-501 and should be
available from any Bourns distributor. TIC wants a lot of extra money
to solder on the three leads they include with it. (Just reuse your
old leads.) It is supposed to be more reliable and more weather
resistant.
John W0UN
============
From: John Brosnahan <broz@csn.net>
To: w2up@itw.com, towertalk@contesting.com
Date: 23 May 1998
Subject: [TowerTalk] TIC Ringrotor indicator problem
At 12:29 AM 5/23/98 +0000, Barry Kutner wrote:
>The indicator on my TIC Ringrotor is starting to act up again -
>needle starts jumping around and rotor stops turning. I believe I
>read somewhere that TIC was working on a fix, like a different kind
>of indicator pot. Anyone know if they ever came up with something
>that keeps on TICking?
>Tnx/.Barry
Barry,
I had an original Clarostat pot fail in my TIC RIng and replaced it
with a similar pot only to have it fail quickly thereafter.
Subsequently I examined both pots and the failures seemed to be
at the point of contact of the wiper arm, or in the wiper arm lead.
I ultimately replaced the pot with a Bourns 3590S-4-501, which is
what TIC Ring is supplying now. This pot is not listed in the
usual distribution sources (they only go down to 1K, not 500 ohms)
but it can be special ordered through the usual distribution channels.
My gut feeling was that there was a chance that the failure mode
was that of picking up RF on the control leads with the RF itself
actually burning up the pot at the point of contact of the wiper arm
or on the fine lead to the wiper arm. Failures would then be
associated with lead dress to some extent and not consistent, which
might explain why some have had failures and others have not. Since
the control leads are almost in the middle of any antenna mounted on
the ring the level of RF could be quite high. If the leads are pulled
open into a loop that is terminated by the pot resistance the
amount of dissipated power could be significant! I once had
an extension cord that was tied in a knot to a small drill actually
melt while in the field of a 10 KW FM transmitter. I have to stop
working those antennas when they are hot! In fact my metal frame
glasses got very hot to the touch, as well!
So, I decided to add bypass capacitors on the terminal strip in the
motor enclosure when I changed to the Bourns pot. I have not had
any more failures but can't be sure if it was just due to the Bourns
pot or to the bypassing of the pot leads.
The whole arrangement of mounting and engaging the teeth on
the pot gear leaves a lot to be desired, so there is still some
suspicion that it is more a mechanical or environmental issue rather
than an RF one, but so far so good.
Hope this info helps.
John W0UN
=====
From: "Tyler Stewart" <k3mm@erols.com>
To: <w2up@itw.com>, <towertalk@contesting.com>
Date: 23 May 1998
Subject: Re: [TowerTalk] TIC RIngrotor indicator problem
Yes. It's almost identical in size to the old one but I think it has
a stainless shaft. Kinda wierd since they are both about 15 bucks and
the Bourns clearly appears to be a superior product. I would call
Carl at TIC and get the exact model number, but if you have the
Digikey catalog, I think it's fairly obvious which one you want.
Gearing should not be affected. Just take the gear off the old one
and put it back on the new. When you put it together, be sure to
approximately center the new pot just in case you get the
wiring wrong and the pot wants to go the wrong way.
Ty K3MM
=====
From: John Brosnahan <broz@csn.net>
To: "Tyler Stewart" <k3mm@erols.com>,
<w2up@itw.com>,<towertalk@contesting.com>
Date: 23 May 1998
Subject: Re: [TowerTalk] TIC Ringrotor indicator problem
At 01:56 PM 5/23/98 +0100, Tyler Stewart wrote:
>John, you must be running that new prototype Alphapower amp! hi!
>
>I have to retract my earlier statement about the Bourns pot being in the
>Digikey catalog, as I couldn't find it there. Maybe it was the Mouser
catalog?
>(Now if I could only find mine!)
>
>Anyway, thanks for the specific number, John.
>
>73, Ty K3MM
Digikey did have the Bourns pots (not sure if they still do) in
their catalog--but they only went down to 1Kohm. I KNOW
TIC gets them through Digikey since one of the people at TIC
is married to someone at Digikey--both are in the same town.
So you should be able to get them through Digikey. When I
bought 10 a month or so ago I paid about $9 each plus shipping.
Don't recall at the moment who I got them from--it was the Bourns
distributor--and Bourns had some of the 500 ohm ones in stock.
John W0UN
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