[R-390] Mechanical Filter Failure?

[John Kolb]

It's possible it's a broken motion coupling wire or the magnostrictive
wire on the coil axis, but from what I've read about R-390A filter problems,
the high probability failure is that the mounting foam degraded creating
a gummy substance which dampens vibrations causing very high
insertion loss.

Graham and Buzz have web sites showing disassembly of the type
of filter where each terminal end of the filter is a separate piece.
http://www.delphelectronics.co.uk/filter390a/
http://webs.lanset.com/buzz/misc/filter/390Afilter.html

This site shows disassembly of the type where there's an
entire metal cartridge inside the outer case.
http://collinsfilter.tripod.com/navigation.htm

John


At 05:25 PM 12/19/2007, ToddRoberts2001 at aol.com wrote:

>Sounds like something mechanical has failed in the discs or the couplers in
>the filter.
>The dead filter would be well worth keeping for the good input and output
>coils.
>Those coils could repair 2 other filters if each had one bad coil.
>Definitely good parts worth keeping!
>
>73 Todd WD4NGG



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