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

[jkharvie]

 Barry,Spot on!Yes - you have spotted an error for the call-out on this drawing, looks like C328 and C327 are in error and switched.  C327 is across primary of T207 per schematic

See attached picture for the location of the capacitor located on the primary of the Transformer

I would like to update the graphics and labeling of the components within the manual, anybody else up for this?

This photo taken of my receiver, the three brown capacitors have been changed out since this photo was taken.



thanks 
John N3JKE



    On Friday, June 28, 2024, 4:07:34 PM EDT, Barry <n4buq at knology.net> wrote:   

 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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