It's on page 6-47 of the Rev 3 document which is what I was looking at. Yes, there's just a bit of difference between 5000pF and 100pF. Actually, I wasn't paying that much attention to the capacitance, just the fact that it was not a Silver Mica cap.
Thanks, Barry - N4BUQ > From: "David Wise" <[email protected]> > To: "Barry" <[email protected]>, "Jacques Fortin" <[email protected]> > Cc: "R-390 Mailing List" <[email protected]> > Sent: Friday, June 28, 2024 3:33:04 PM > Subject: Re: [R-390] Update on R390A, open question regarding scope and > options > fir lubrication > ERRATA TIME! > In Figure 6-21, the annotations for C327 and C328 are swapped. C328 is a 5nF > ceramic disk bypass, while C327 is 100pF mica forming a tuned circuit. > Jacques, did you typo? Figure 6-21 is on page 6-59, not 6-47, at least in my > file which says Revision 10, 2006-March-17. > Dave Wise > From: [email protected] <[email protected]> on behalf > of > Barry <[email protected]> > Sent: Friday, June 28, 2024 1:07 PM > To: Jacques Fortin <[email protected]> > Cc: R-390 Mailing List <[email protected]> > Subject: Re: [R-390] Update on R390A, open question regarding scope and > options > fir lubrication > I just opened the Y2K-R3 document and on page 6-47, Figure 6-21 shows a > picture > of C327 which appears to be a ceramic disc. Is that a mistake in the Y2K > documentation? Apologies if this has already been discussed but I found it odd > in light of all this recent conversation regarding C327. > Thanks, > Barry - N4BUQ > > John, unless that you are equipped to test the Micamold cap with 300Vdc > > applied > > (their manufacturing voltage rating) to confirm that they have less than > > 10nA > > of leakage, wait for the new manufacture 1kV one. > > I believe that the recommendation to change C327 was made because of the > > trouble > > involved with the RF deck removal to change any of the parts within. > > Since then, many original mica caps inside the IF transformers were > > reported to > > fail (the thunderstorm noise problem). > > But here also, they will not ALL exhibit failures, as this is just a > > probability. > > Failure of the early type "postage stamp" mica caps is essentially due to > > their > > long-term casing permeability. > > Some mica caps were made to never fail, like the Corning Glass Works (CGW) > > ones > > that have a glass encapsulation. > > But as with any electronic equipment ever made, all depended on the cost vs > > reliability criteria. > > 73, Jacques, VE2JFE in Montreal > > ______________________________________________________________ > > R-390 mailing list >> Home: [ http://mailman.qth.net/mailman/listinfo/r-390 | > > http://mailman.qth.net/mailman/listinfo/r-390 ] > > Help: [ http://mailman.qth.net/mmfaq.htm | http://mailman.qth.net/mmfaq.htm > > ] > > Post: [ mailto:[email protected] | mailto:[email protected] ] > > This list hosted by: [ http://www.qsl.net/ | http://www.qsl.net ] >> Please help support this email list: [ http://www.qsl.net/donate.html | > > http://www.qsl.net/donate.html ] > ______________________________________________________________ > R-390 mailing list > Home: [ http://mailman.qth.net/mailman/listinfo/r-390 | > http://mailman.qth.net/mailman/listinfo/r-390 ] > Help: [ http://mailman.qth.net/mmfaq.htm | http://mailman.qth.net/mmfaq.htm ] > Post: [ mailto:[email protected] | mailto:[email protected] ] > This list hosted by: [ http://www.qsl.net/ | http://www.qsl.net ] > Please help support this email list: [ http://www.qsl.net/donate.html | > 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
