[R-390] A question about silver-mica capacitors failures.

[Larry H]

Hi Jacques,  From what I've read and experienced, both are a factor.  An SM
cap just sitting there with no voltage applied will eventually go bad.
But, if it has DC voltage applied to it, the migration seems to occur
quicker.  What's interesting is that this does not mean that all SM caps
with potential applied will fail before those that do not.

Regards, Larry

On Sun, Mar 29, 2020 at 12:28 PM Jacques Fortin <jacques.f at videotron.ca>
wrote:

> It was flagged by many contributors to this site that the number of silver
> mica capacitors failures is rising.
>
> As the failure mechanism seems to be understood (silver migration within
> the
> capacitor package), it is not clear for me if this occurs only when a
> potential difference is applied to these capacitors, or if it can be
> triggered only by the time, even if the radio containing those capacitors
> was left unpowered for years.
>
> I will appreciate to know your thoughts about it.
>
>
>
> 73, Jacques, VE2JFE
>
>
>
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