[R-390] Collins R-390A, new owner

[Dave Maples]

All: While we are discussing paper cap replacement, I seem to have very good
success with the polypropylene caps sold at Antique Electronics Supply (no
relation).  I did Orange Drops for my R-390A IF upgrade, but have found the
caps at AES to be easier to work with (true axial caps vs. the "radial"
Orange Drops).  Specs appear to be as good or better AFAIK.

Anyone else ever used these?

Thanks,
Dave WB4FUR

-----Original Message-----
From: r-390-bounces at mailman.qth.net
[mailto:r-390-bounces at mailman.qth.net]On Behalf Of
Flowertime01 at wmconnect.com
Sent: Tuesday, August 28, 2007 2:45 PM
To: R-390 at mailman.qth.net
Subject: Re: [R-390] Collins R-390A, new owner


Rasputin,

Tom pointed out the major two problems.
Power hum leads you to checking the filter caps.

The filter coupling capacitor C553  in the IF deck for the mechanical
filters
is the next major item to inspect for. Considering that if it fails, it will
let the mechanical filters also be burnt open for no good reason.

Inspection is a two clamp four green screw and four connector operation.
Cheap and easy to do.

The next item is all the old 0.01 large dia 1/2 inch long 1 1/2 inch likely
brown but some times black (depending on production run) by pass caps. C553
listed above is one of these caps.

If your IF deck has lots  of space and many nice new smaller caps in it then
you have a deck that has been reworked. If your deck has about a dozen of
the
old large plastic caps then you will want to consider replacing all of them
over time.

There are also a couple under the RF deck. If you have a need to pull the Rf
deck off the chassis you will want to replace the large plastic caps under
that sub chassis deck as well.


There is one small electrolytic in the audio deck that liked to leak as far
back as the late 60's. You may want to look in the Audio deck as well and
inspect that cap.

Have you found the R390 web pages with the TM's Y2K manual and the Pearls of
Wisdom?

Welcome aboard.

Roger L. Ruszkowski AI4NI
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