[R-390] Filter cap temperature

[Cecil Acuff]

Just a comment on the black goo.  Maybe I got lucky but I did no digging at 
all.  I did find if you pull on them before they are heated enough on the 
outside you will leave a bunch of the stuff up in there to have to get out. 
I took a propane torch and heated the shell while the base was locked in a 
soft jawed vice.  Once it started smoking a bit from inside I grabbed the 
outer shell with something that kept me from getting burnt but allowed 
decent grip and snatched the thing off.  All I was left with was a thin film 
of the goo in the inside of the shell.  I wiped it out with a piece of cloth 
wet with flux remover or lacquer thinner.  Worked great.  I rushed the next 
one and ended up with the top half of the goo to get out.  More heat and a 
screwdriver and it popped right out.  It's not too hard.  It just requires 
more heat than most expect!  A heat shrink gun didn't get it!

Cecil...
----- Original Message ----- 
From: "Barry" <n4buq at aol.com>
To: "R-390 HF Receiver List" <r-390 at mailman.qth.net>
Sent: Friday, May 06, 2005 9:56 AM
Subject: Re: [R-390] Filter cap temperature


>I did "caps in an octal socket" for my Motorola.  It works nicely, but I
> don't really see that much advantage to having them "plug-n-play".  I'm
> thinking of doing what I saw someone else do.  Using axial-lead caps, run
> the positive lead through the appropriate hole in the socket and solder
> underneath.  Gather the negative leads together, solder them to a ground 
> lug
> and attach the ground lug to the standoff where the original cap clamp
> attached.  I thought that was a pretty neat solution.  Digging out
> ukkumpucky gets old.
>
> Barry - N4BUQ
>
>
>
>> I think a rebuild is a standard thing with the "A".  I have several in 
>> the
>> shop and everyone I have checked had excessive leakage.
>>
>> I would do the rebuild.  There are several ways to go...caps under the
>> chassis, caps in octal socketed square relay housings or the traditional
> cap
>> overhaul where you cut the things open and replace the guts.  I am about
>> half way through that process with a pair of mine but have had to put it
> on
>> the back burner for a few weeks while I finish another project up!
>>
>> Cecil...
>> ----- Original Message ----- 
>> From: "Barry" <n4buq at aol.com>
>> To: "R-390 HF Receiver List" <r-390 at mailman.qth.net>
>> Sent: Friday, May 06, 2005 8:36 AM
>> Subject: [R-390] Filter cap temperature
>>
>>
>> > While tinkering with the "new" R390A last night, I noticed that C603 is
>> > getting slightly warm.  The other cap is cold.  Is this possible an
>> > indication of low ESR?  Do these old caps generally leak a bit or 
>> > should
> I
>> > be concerned?  I hadn't planned on replacing them as they seem to be
>> > working, but if they're going to blow, then I'd rather go ahead and
>> > replace/rebuild them.
>> >
>> > Thanks,
>> >
>> > Barry - N4BUQ
>
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