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
