I think that's correct, but I wasn't able to find the -3 or -4 pots in small
quantities or reasonable prices. Nevertheless, N3RS has been using the -1
pots for years with no failures. YMMV (and mine, for that matter -- we'll
see.)
The Bourns pots have four small holes in the bottom of the case. I can't
tell if these lead to the interior of the pot, but it looks that way. It
could be that these holes allow sufficient drainage or venting to prevent
moisture buildup, and may be the real reason why they work better than the
Vishay pots, which don't have holes in the bottom.
There are oil-filled pots that would probably work best for this
application. But they're over $200 apiece and the form factor would probably
require modifying the pot compartment cover.
73, Dick WC1M
> -----Original Message-----
> From: Michael Keane K1MK [mailto:k1mk@alum.mit.edu]
> Sent: Friday, June 19, 2009 2:54 PM
> To: Dick Green WC1M
> Cc: 'Henk Remijn PA5KT'; Tower Talk
> Subject: Re: [TowerTalk] Tic rotor potmeter replacement?
>
> According to its spec sheet, a 3590S-1-501 is unsealed against water
> (IP40).
>
> A 3590S-3-501 (plastic bushing) or 3590S-4-501 (metal bushing) variants
> are sealed against a water jet from any angle (IP65)
>
> 73,
> Mike K1MK
>
> On 6/19/2009 2:19 PM, Dick Green WC1M wrote:
> > Henk,
> >
> > The most recent pots I got from TIC are Vishay model 534. It's a 10-turn
> > pot, 500 ohms +/- 5%, linearity +/- .25%.
> >
> > However, I've seen quite a few of these pots fail due to moisture
ingress,
> > sometimes accompanied by freezing. I have recently obtained what may be
a
> > superior replacement: Bourns model 3590S-1-501. This pot has identical
> specs
> > and dimensions to the Vishay pot, but has a plastic body and shaft, as
> > opposed to the Vishay's metal body and shaft. Here is a link to the spec
> > sheet:
> >
> > http://www.bourns.com/data/global/pdfs/3590.pdf
> >
> > N3RS told me he replaced the stock pot with the Bourns model quite a few
> > years ago and has not had any problems since. He believes the Bourn pot
is
> > better sealed against moisture than the pot provided by TIC. I have
three
> of
> > the Bourn pots on hand but have not attempted to disassemble them to see
if
> > they are in fact better sealed. My sense is that moisture trickles down
the
> > shaft and into the body of the pot because the shaft is in a vertical
(up)
> > orientation. Although the motor case is sealed, eventually moisture
finds
> > its way to the pot, either through leaks in the case or condensation. If
> the
> > Bourn pot has an O-ring or some other type of seal at the shaft-body
> > interface, it may be more resistant to moisture than the Vishay pot.
> >
> > 73, Dick WC1M
> >
> >> -----Original Message-----
> >> From: Henk Remijn PA5KT [mailto:pa5kt@remijn.net]
> >> Sent: Friday, June 19, 2009 11:31 AM
> >> To: Tower Talk
> >> Subject: [TowerTalk] Tic rotor potmeter replacement?
> >>
> >> Hi,
> >>
> >> I own a Tic rotor 1032 and the potentiometer stopped working. I know it
> >> can be a cabling problem, but if the potmeter is the problem I want to
> >> have the right parts available I would like to buy a replacement
potmeter.
> >>
> >> Does someone know what potmeter is inside?
> >>
> >> 73 Henk PA5KT
> >>
> >> --
> >> Henk Remijn PA5KT
> >> email: pa5kt@remijn.net
> >> www: www.remijn.net
> >>
> >
> >
> > _______________________________________________
> >
> >
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> >
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|