[R-390] The OD discussion (Dead Horse Walking)

[Craig C. Heaton]

For those who haven't been on this list, once again the capacitor question
has appeared numerous times. It is a dead horse walking and needs to be
beaten once more. Go back into the archives and check out previous post,
some great reading on the subject of; if you recap, the need to recap, don't
recap, etc.

So: Rule #1: It's your radio, your money, your time spent.
    Rule #2: Read Rule #1.

My money is to replace BBOD's with orange drops, they have a proven track
record. I'd like my receivers to outlast me. And this should be rather easy,
I've more to look back on than time will give me for the future. Since the
R-390/A is belly up, might as will replace the electrolytic caps at this
time. Then plug it in.

As final food for thought we will resurrect dead horse #2, the R-390 (non
A). This fine radio was the predecessor of the R-390/A. In the early 1950's
the non A was deemed  costly to produce and needed a few improvements.
Please read the following link, Cost reduction program for radio receivers
R390/r391()urr.

Please note on page 6 of this document, third paragraph, "In the field of
components, capacitors in particular proved quite costly."

http://www.r-390a.net/faq-refs.htm

For some reason, the engineers which designed our beloved R-390/A chose not
to use ceramic disc caps for bypassing, etc. There has to be a reason why it
has such a large following and is thought to be the best vacuum tube
receiver built!

Feel free to break out the Cat "o" Nine Tails.

73's
Craig



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Hi Guys,

I've been reading with interest the discussion about recapping and the 
use of 'Orange Drops'. I bought a bunch of the 716 series from AE a 
while ago (enough to do a full recap on one R-390A) and I bought enough 
silver mica caps from Mouser to do an IF strip rebuild.

The reason I chose those particular types is what I perceived as their 
reputation for quality and reliability and as one list member said...I 
only want to rebuild/remanufacture my radio once! It's not going to be a 
museum piece, it's going to be a radio that I want to use on the daily 
basis for the rest of my life.

Having said that though...do you guys think I have gone overboard with 
my choices (716 series Orange Drops and Silvered Mica) as I've read that 
Ceramics seem to be good enough to use almost everywhere. The reason 
that I didn't choose Ceramics is that I read somewhere that the Silvered 
Mica were a step up from the Ceramics.

I have a further three R-390 series radios that are going to get the 
full rebuild treatment so if there is a better choice out there I'd like 
to know. The radio I'm am doing at the moment is my first R-390A rebuild 
and I am planning on doing one a year...then I can sit back and relax 
and enjoy the fruits of my labors!

Regards,
Ken