[R-390] Re: Busted mechanical filters

[Craig C. Heaton]

I forget which website and/or discussion but the cotton balls were used in
another style of mechanical filter other than those used in a R-390/A. The
2KC filter which I disassembled from a R-390/A uses something closer to a
type of soft black rubber 5/16 of an inch thick.

My money says, just about anything which would hold the disks/coils will
work. A die to cut out little rubber supports should be a piece of cake for
anyone with access to a machine shop. I don't think any of this is rocket
science: find something to dissolve the black stuff holding the windings on
the coils, count the numbers of turns, rewind with correct size magnet wire,
new supports if needed. Or could gather a bunch of old mechanical filters
and use the pieces to build a good one.

Then test the results.

Craig,

-----Original Message-----
From: r-390-bounces at mailman.qth.net
[mailto:r-390-bounces at mailman.qth.net]On Behalf Of Drew Papanek
Sent: Monday, October 02, 2006 2:57 PM
To: r-390 at mailman.qth.net
Subject: [R-390] Re: Busted mechanical filters




Jim Miller wrote on the topic of mechanical filter repair:

>But how do you reassemble it?  What do you
>use for replacement foam, etc.

ISTR a post where someone had used cotton balls in
place of the foam.  Anyone care to comment?

Drew


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