[R-390] Collins Mechanical Filters

[David Wise]

Thanks, Craig!  (Leigh, someday I'll do that one you sent me, I promise.)

I have a big roll of fine-gauge wire at home.  I'm sure it's 30-something.
I'll measure it tonight, and I'll be happy to mail you 10m or so.

Dave

> -----Original Message-----
> From: r-390-bounces at mailman.qth.net
> [mailto:r-390-bounces at mailman.qth.net]On Behalf Of roy.morgan at nist.gov
> Sent: Sunday, April 23, 2006 8:46 PM
> To: Craig C. Heaton
> Cc: R-390A
> Subject: Re: [R-390] Collins Mechanical Filters
> 
> 
> Quoting "Craig C. Heaton" <wd8kdg at worldnet.att.net>:
> ..here is a link to a little website I've put together. It 
> tells how to open a
> Collins Mechanical Filter for a R-390/A and includes photos.
> 
> Craig,
> 
> Thanks much for the website and phtotos on the mechanical filers.
> 
> It seems to me that your next steps are:
>  
> 1) find the required number 39 wire
> 2) find out how to dissolve the "black material" that was 
> applied to the
> windings so you can: a) remove them  b) count them so as to 
> rewind them with
> the right number of turns.
> 
> I have a suggestion for 2):
> Mix up some "de-gooper": one third each acetone, MEK, and 
> acetic acid. This
> stuff is bad for you, but you only need a little bit. Immerse 
> the coil in it
> for day or five and see what happens.  I have used this stuff 
> in the past (back
> in the 60's) to remove some epoxy potting compound on somne 
> IBM logid modules.
> It strips some component markings but you don't care about 
> that. Likely it will
> dissolve the black stuff. It may dissolve the coil form but 
> it's worth a try.
> 
> I may have some number 39 wire but I'm in the middle of a 
> major upheaval with
> most of my Junque and Treasure gone to storage as I get ready 
> to move to a new
> and better place for radios, including my collection of R-39x 
> sets. Soo.. I may
> not be able to locate any of the fine wire I have.
> 
> I do have at least two 4kc filters here that have failed: it 
> sounds like your
> methods will come in handy. Thanks for posting them.
> 
> Roy
> K1LKY
> 
>  
> 
> Roy Morgan
> 7130 Panorama Dr.
> Derwood MD 20855
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