[R-390] First time R-390 Owner

[Jacques Fortin]

Hi Adam,
The owners of the R-390/URR receivers generally agree that they are less
easy to work on than the R-390As.
The problems are different...
Some wrote that the R-390A is a boy radio, the R-390 is a man radio...

Let's begin with the basics:
What are the maker, contract number and serial of this R-390/URR ?

The capacitors inside a R-390 usually do not need to be replaced, they were
all sealed glass-metal enclosed Sprague "Vitamin Q" originally.
So they should be as good as when they came out of the production line.
EXCEPT, if you find some with external signs of oil swelling.
On this ones the seal failed and the air oxygen contaminated the
impregnating oil, leading to the common PIO "leakage" syndrome.
I just found 3 or 4 "failed" ones in my own R-390.
And, BTW, the power supply oil-filled 10µF should still be good also: no
need to replace it.

HOWEVER, the AB solid carbon resistors used within were not made to survive
that long: I had to change about 30% of those, especially in the AF/PS deck
because of the heat generated by the 6082 regulator tubes when the set
operates.

If this set was never "restored" before, YOU WILL NEED to go in the RF deck.
Be sure that the "Green Gear" is still in his parking spot: you will need it
!!!

There is three TMs available for the R-390/URR.
The most useful to me was the original Collins Manual for it that you can
find here:
https://www.royalsignals.org.uk/radio-rx-R390/2460.pdf
Then the TM11-856 and the TM11-5820-357.

Anyways, take your time, any information you may need, just ask !
We've been there !


73, Jacques, VE2JFE in Montreal

-----Message d'origine-----
De : r-390-bounces at mailman.qth.net <r-390-bounces at mailman.qth.net> De la
part de Adam Morehouse
Envoyé : 12 août 2025 11:11
À : r-390 at mailman.qth.net
Objet : [R-390] First time R-390 Owner

Hey guys,

Long time lurker here. You fellas helped me through my R-390A restoration
(which just got back from Bill Riches for his finishing touches). This
weekend I purchased an R-390, and another R-390A. Both them are are pretty
pristine - faces are great, extremely clean inside. The R390A has some
weirds to the IF deck and Audio deck, which I haven't figured out....the
R390 looks untouched.

I am not very smart with electronics - I'm a young man, and typically
restore old Philcos, Zeniths, etc as a hobby. Replacing caps and resistors I
can do. Everything else confuses me, but I am trying to learn, especially
since I've got a growing collection of communication receivers.

Supposedly, the R390 went to Rick Mish around 2004 - I think the owner might
be confused with the R-390A, as it's cleaner than new inside. The
R390 looks untouched. I am sad that there doesn't seem to be as many
articles, etc for the non-A...I do some original TM's on the way.

In order to test thing, what are the bare minimum caps/resistors to replace?
I haven't torn it down yet - I see a 10uF can behind the front cover, and
what looks like an oil filled cap near the P/S. Hopefully nothing under the
RF deck needs to be looked at, as that seems like a bear compared to the
R390A.


Thanks for any help, or advice. I really appreciate it!

Adam K2AAM
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