[R-390] saga cont pt 12
rbethman
rbethman at comcast.net
Mon Sep 27 17:05:40 EDT 2010
The brown molded mica, (postage stamp mic), are paper caps inside.
Same failure mode of the Black/Brown Beauties and Tiny Chiefs.
The Red mica caps are the silver mica construction, and suffer from
silver migration, throwing values all over the map.
Replace them with a good quality disc ceramic.
Bob - N0DGN
On 9/27/2010 4:45 PM, David Wise wrote:
> Leakage is a frequent failure mode in molded mica caps today.
> Besides messing up the DC operating point, it spoils the Q.
> And most of the ones I've seen, only leaked under voltage.
> As some of the caps are in the R-390A.
>
> Dave Wise
> SWL in Hillsboro Oregon
More information about the R-390
mailing list