Hi Jacques, One end is connected to R560 and the other end is connected to Z503. I'm not sure but I think it's R554 and was likely changed from 2.2k to 470 ohms. Either that, or R554 was mislabeled from the beginning. I do see where that resistor is still 2.2k for the R-390A/URR so not sure how it ended up being 470 ohms in these radios.
Thanks again, Barry - N4BUQ > Hi Barry, > > Eeer... Is that "470 ohms" resistor connected at the same post than the 56K in > the picture ?? > Where the other end of it is going ? > And if your R560 measures 68K, change it ! > It will affect the Carrier Meter calibration and the AGC time constant in > "slow" > mode. > > 73, Jacques, VE2JFE in Montreal > > -----Message d'origine----- > De : [email protected] <[email protected]> De la part > de > Barry Scott > Envoyé : 13 octobre 2024 23:03 > À : Jacques Fortin <[email protected]> > Cc : R-390 Mailing List <[email protected]> > Objet : Re: [R-390] Mystery Component > > I'd originally started looking at R560. It's about 68k in mine. Not really > sure how critical that is and I think at most it might have some effect on the > AGC time constant. > > I'm pretty sure now, though, that the "mystery" component is a 470 ohm > resistor. > Another list member sent a picture of a couple of his IF modules and one is > clearly 470 ohms. That last band is brown instead of orange. Mine is > checking > a bit over 500 so probably good enough as-is. Odd, though, that they used one > of the "older" style resistors there. That's what threw me off more than > anything. > > Thanks, > Barry - N4BUQ > > On Sun, Oct 13, 2024 at 8:41 PM Jacques Fortin <[email protected]> wrote: >> >> Barry, >> That "mystery" component is R553. >> From your picture, a 1W, 47K ohms, 10% IRC brand resistor (maybe not the >> original one, but who knows ??). >> It connects the 180V supply to the screen grid of V509. >> R560 (56K ohms) can be seen in the same picture. >> >> 73, Jacques, VE2JFE in Montreal >> >> -----Message d'origine----- >> De : [email protected] <[email protected]> De >> la part de Barry Envoyé : 13 octobre 2024 18:15 À : R-390 Mailing List >> <[email protected]> Objet : [R-390] Mystery Component >> >> Maybe not really a “mystery” but I can’t identify the dark brown cylinder >> with >> one yellow and two brown(?) stripes in the AGC time-constant compartment in >> my >> R-490/URR. A 410-ohm resistor? >> >> If those are actually violet stripes then I’m even more confused. Anyone >> know? >> >> >> ______________________________________________________________ >> 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 ______________________________________________________________ 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
