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

[jkharvie]

Jacques,Greetings to Montreal.  Thank you for your expertise and explanation.The capacitor being replaced is of a greenish plastic, rectangular form factor.   I count in the underside of the RF sub chassis, 18 of this type installed.   See picture where improper type was installed, it is a bright blue.  This will be changed out for the proper component.I have purchased a 100pf, 1000 volt mica type replacement to place across the primary of this RF transformer. Passive leakage assessments conducted on these capacitors show no signs of leakage, bulging of case, or out of tolerance capacitance.  Under voltage testing not conducted, i understand this is the proof of performance   Is the consensus recommendation to also swap out all of these?



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  On Fri, Jun 28, 2024 at 0:00, Jacques Fortin<jacques.f at videotron.ca> wrote:   John, the original capacitor is prone to fail not because of it's voltage rating, but because of it's encapsulation.
The original capacitors were molded in phenolic which let the oxygen slowly came in, helping internal silver migration and capacitor failure.
Any modern epoxy-encapsulated part will last longer than the original one.
A 5% tolerance will be fine, and a 500V rating is also OK, but indeed, a 1kV rating will be better.

73, Jacques, VE2JFE in Montreal

  
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