[R-390] Update on R390A, open question regarding scope and options fir lubrication

[Barry]

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" <d44617665 at hotmail.com>
> To: "Barry" <n4buq at knology.net>, "Jacques Fortin" <jacques.f at videotron.ca>
> Cc: "R-390 Mailing List" <r-390 at mailman.qth.net>
> 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: r-390-bounces at mailman.qth.net <r-390-bounces at mailman.qth.net> on behalf of
> Barry <n4buq at knology.net>
> Sent: Friday, June 28, 2024 1:07 PM
> To: Jacques Fortin <jacques.f at videotron.ca>
> Cc: R-390 Mailing List <r-390 at mailman.qth.net>
> 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

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