Plate cap. Do you mean C553? Was it a Vitamin Q? ________________________________ From: r-390-boun...@mailman.qth.net <r-390-boun...@mailman.qth.net> on behalf of Renee K6FSB <k6fs...@gmail.com> Sent: Tuesday, August 12, 2025 3:48 PM To: Jim Whartenby <old_ra...@aol.com>; R390A List <R-390@mailman.qth.net> Subject: Re: [R-390] First time R-390 Owner
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 >>> ______________________________________________________________ >>> R-390 mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/r-390 >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:R-390@mailman.qth.net >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ > R-390 mailing list > Home: http://mailman.qth.net/mailman/listinfo/r-390 > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:R-390@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ > R-390 mailing list > Home: http://mailman.qth.net/mailman/listinfo/r-390 > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:R-390@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ R-390 mailing list Home: http://mailman.qth.net/mailman/listinfo/r-390 Help: http://mailman.qth.net/mmfaq.htm Post: mailto:R-390@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ R-390 mailing list Home: http://mailman.qth.net/mailman/listinfo/r-390 Help: http://mailman.qth.net/mmfaq.htm Post: mailto:R-390@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
