[R-390] paper capacitors

[Cecil]

I'm not a proponent of that.  There are some documented cases where silver migration in some of the silver micas has caused a problem but those are great examples of fix them when they fail and don't disturb those that are still working fine.  That philosophy works here because they fail so infrequently and wholesale replacement of those will most definitely upset many things in the receiver.  Full alignment being necessary....and again once some aging takes place.  Best to leave those alone unless you have no choice.

Do replace the ugly tantalum and the filter caps...both good suggestions for a restoration....maybe even the AGC cap...

Cecil...

Sent from my iPad

> On Nov 30, 2014, at 3:23 PM, Bob Camp <kb8tq at n1k.org> wrote:
> 
> Hi
> 
> It’s not just the paper caps that people are replacing. “Re-capping” the radio seems to extend to every single cap anywhere and everywhere inside the box.
> 
> Bob
> 
>> On Nov 30, 2014, at 11:48 AM, Cecil <chacuff at cableone.net> wrote:
>> 
>> What's strange to me is that if we were having this discussion on a Hammarlund, Hallicrafters or National list it's pretty much an accepted fact that one of the first things one would do in a restoration would be to replace the paper coupling/bypass caps...black beauties, brown beauties, tiny chiefs you name it.  But we continue to debate the issue as it relates to the "A" series of the R-390 receiver when in truth the paper caps used in its build are of only marginal if any improvement over those used in consumer grade communications receivers of the same period.
>> 
>> It's even accepted that all the Hunts brand coupling/bypass caps in the military Racal RA-17 series have to go due to electrical leakage issues....(ask me how I know)
>> 
>> What makes the R-390A special (read exempt)?
>> 
>> Cecil
>> 
>> Sent from my iPad
>> 
>>> On Nov 30, 2014, at 9:41 AM, Bob Camp <kb8tq at n1k.org> wrote:
>>> 
>>> Hi
>>> 
>>> This is why I cringe a bit when people decide to wholesale re-cap some of these radios. The parts in there have made it past infant mortality and various instal / damage issues. You are trading one set of things for another.
>