Barry, I was going to try my hand at putting them together and getting them working. If I can pull that off, I'd be more than happy to help the R390 community out, probably for the cost of the board and components, which isn't too bad.
This is just a college hobby of mine, not looking to sell anything :) On Wed, Oct 8, 2025, 13:27 Barry <[email protected]> wrote: > Adam, > > What did you plan to do with those boards? I might be interested in one > if available. > > Thanks, > Barry - N4BUQ > > > The only mod I had planned was using a Treetop Circuit SSB board. I had > > ordered boards from PCB express using TTC's design and was going to try > to > > piece one together, and when I picked up this R390 it came with one that > > was never installed. > > > > The mod doesn't seem to work very well, let me take a closer look and see > > if I can notice any mistakes, now that I have the documentation for it! I > > appreciate it sir. > > > > Adam > > > > On Wed, Oct 8, 2025 at 12:06 PM Jacques Fortin <[email protected]> > > wrote: > > > >> Hi Adam, > >> No need for an "original" BFO switch. > >> As the W3JHR mod. used a DPDT one, and if it is still fitted there, only > >> half of it can be used as a BFO power sw. > >> Check how the V508 socket is wired in your IF deck: that should confirm > >> that it was modified to use a 6BE6. > >> You can also keep the mod. in place (if it works) unless you want to > have > >> an "original" R-390, meaning without a product demodulator fitted in. > >> > >> 73, Jacques, VE2JFE in Montreal > >> > >> -----Message d'origine----- > >> De : [email protected] <[email protected]> De > la > >> part de Adam Morehouse > >> Envoyé : 8 octobre 2025 11:53 > >> À : Jacques Fortin <[email protected]> > >> Cc : R-390 Mailing List <[email protected]> > >> Objet : Re: [R-390] R-390 Woes > >> > >> Well that's interesting, I guess I'll need to find an original BFO > switch. > >> No wonder the thing didn't work, there are no substituted tubes in it. > Now > >> I get to figure out how to undo all of this. > >> > >> :( > >> > >> On Wed, Oct 8, 2025, 10:18 Jacques Fortin <[email protected]> > wrote: > >> > >> > Hi Adam, > >> > > >> > I think I recognise this mod., the clue being the 56k resistor in the > >> > picture. > >> > > >> > See attached doc. > >> > > >> > If it is really the original W3JHR mod. that was implemented there, > >> > the BFO on/off switch has been also changed for a DPDT version > >> > (switching the audio input between the AM and product detectors and > >> > powering the BFO oscillator at the same time). > >> > > >> > If it is that, the BFO tube (V508) have to be a 6BE6/5750 instead of a > >> > 6BA6/5749… > >> > > >> > This is basically the same product detector that I use in my own R-390 > >> > and R-390As, by using a changeover relay inside the IF deck instead of > >> > using a substitute BFO switch. > >> > > >> > See also the W7DI type of implementation attached. > >> > > >> > Larry Haney also worked around this theme and used a 6BY6 tube for the > >> > product detector because it works better than a 6BE6 in the same > >> > configuration. > >> > > >> > I also worked with Larry to find a way to still use the noise limiter > >> > in the SSB mode, but the result of our experiments are not final, and > >> > the AGC modifications we devised to “improve” the R-390 / 390A are > >> > still not fully tested. > >> > > >> > Stay tuned, I should have time to re-visit that during the next > winter. > >> > > >> > > >> > > >> > 73, Jacques, VE2JFE in Montreal > >> > > >> > > >> > > >> > -----Message d'origine----- > >> > De : [email protected] <[email protected]> De > >> > la part de Adam Morehouse Envoyé : 8 octobre 2025 03:44 À : R-390 > >> > Mailing List <[email protected]> Objet : Re: [R-390] R-390 Woes > >> > > >> > > >> > > >> > I might have found the issue. > >> > > >> > > >> > > >> > Can anyone tell me if the white coax in the follow pictures is > supposed > >> to > >> > be there? > >> > > >> > > >> > > >> > https://photos.app.goo.gl/M6Qcr9mXFrZ6sgiRA > >> > > >> > > >> > > >> > It doesn't look original to me, nor does the the resistors and caps in > >> > front of the BFO. They seem to be hooked to V508 and RT512. > >> > > >> > > >> > > >> > > >> > > >> > > >> > > >> > > >> > > >> > On Tue, Oct 7, 2025, 16:55 Adam Morehouse <[email protected]> > wrote: > >> > > >> > > >> > > >> > > Hey guys, > >> > > >> > > > >> > > >> > > I appreciate the pointers on my R-392, and now that it's buttoned > up, > >> > > >> > > it's time to work on my R-390. I only tested this briefly when I > first > >> > > >> > > got it, today I threw it up on the bench. Supposedly this was > restored > >> > > >> > > by Rick Mish, it is very clean (except the gear train, which has a > lot > >> > > >> > > of fresh grease...), and the front panel is pristine. > >> > > >> > > > >> > > >> > > It does pull stations, but the volume is extremely low in AGC mode, > >> > > >> > > and gets slightly louder when placed into MGC. > >> > > >> > > > >> > > >> > > In MGC, with the BFO switched on, it plays at a normal (not super > >> > > >> > > loud, but loud) volume. > >> > > >> > > In AGC, with the BFO switched on, it hums, low volume audio. > >> > > >> > > > >> > > >> > > The limiter seems to have no effect, and varying the BFO doesn't do > >> > > >> > > anything at all no matter AGC/MGC. > >> > > >> > > > >> > > >> > > I have Tom's solid state kit installed, and B+ at the AF deck test > >> > > >> > > point is a steady 180.5vdc. > >> > > >> > > > >> > > >> > > I am going to dig out the TM's later on, I have them somewhere...but > >> > > >> > > maybe somebody here can help point me in the right direction. > >> > > >> > > > >> > > >> > > Thanks! > >> > > >> > > > >> > > >> > > Adam K2AAM > >> > > >> > > > >> > > >> > > > >> > > >> > > > >> > > >> > ______________________________________________________________ > >> > > >> > R-390 mailing list > >> > > >> > Home: http://mailman.qth.net/mailman/listinfo/r-390 > >> > > >> > Help: http://mailman.qth.net/mmfaq.htm > >> > > >> > Post: mailto:[email protected] <[email protected]> > >> > > >> > > >> > > >> > 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:[email protected] > >> > >> 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:[email protected] > > > > 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:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
