Jim-
I obtained a failed R390A deck where the plate cap was extremely leaky
and 2 of the filters plate side were open. I do not recall all the
history other than I replaced the cap and the filters....I tossed the
bad ones...put the deck in a "build". I saved the cap for years as it
was a proof that some caps do go bad...It is long gone now. wish I had
kept the filters......
the only other caps in a r390 that had issues were last IF audio filter
red postage stamp, either a 100 or 180 was shorted.
Oh wow that brings back memories....I do recall another poor R390 was in
sad sad shape as well, it had spent more than a few summers and winters
out doors- no covers, mice nests, bug nests, and mud in everything,
weeds growing..... thank goodness for soap and a hose! it was like it
had been stored in a flood plain/ middle of a field. In the end it
played, that was a lot of work! oh yea the big problem besides filthy
dirty - cables- RF and one or two of the audio cables were bad too. I do
not recall any caps tho..geee this goes way back. I was a kid did not
know much then! I learned a lot...especially what that silly green gear
did! HiHi
Renée
On 8/12/25 9:43 AM, Jim Whartenby via R-390 wrote:
Speaking of which, does anyone have first hand knowledge of loosing a
mechanical filter due to a leaky or shorted C553? I know Henry Rogers mentions
having some bad R-390A mechanical filters but the failure was on the grid side
of the filter, not the plate side. I think that it has more to do with the
reliability of those early mechanical filters then to a leaky C553.
I have repaired a few of the mechanical filters used in the R-390A. The
problem is usually a broken transducer wire connected to the internal solder
terminal. This is sometimes caused by the rubber isolator turning into goo and
allowing the internals to slide down inside the tube and stress the transducer
wires. It also could be due to a hard drop of the R-390A since those
mechanical filters are mounted vertically. It is a little tricky unsoldering
the end bells and replacing the isolator rubber but it is not that difficult.
This is my experience but YMMV.Jim
Logic: Method used to arrive at the wrong conclusion, with confidence. Murphy
On Tuesday, August 12, 2025 at 10:58:17 AM CDT, Adam Morehouse
<morehous...@gmail.com> wrote:
Hey Barry,
I have not yet - I wanted to check in and make sure there aren't any
components that should be changed before a test, like the filter killer cap
in the A model.
Adam
On Tue, Aug 12, 2025 at 11:46 AM Barry <n4...@knology.net> wrote:
Hi Adam,
While I only have a sample size of one R390, I think you may find the
components in these are much more likely to still be good and there may not
be that many "replace on sight" components as might be in other radios.
Have you powered it up to see how it behaves?
73,
Barry - N4BUQ
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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