[R-390] saga cont pt 12
rbethman
rbethman at comcast.net
Mon Sep 27 17:21:23 EDT 2010
Personally, I'd unsolder one end and test them.
Although I haven't had an issue with them to date.
There are some "smallish" Sprague silver ones with radial leads. Those
have all tested good.
Bob - N0DGN
On 9/27/2010 5:14 PM, ka9egw at britewerkz.com wrote:
> how about the little cylindrical radial-leaded ones and the mint-green ones?
> 73 Brian KA9EGW
>
> -----Original Message-----
> From: r-390-bounces at mailman.qth.net
> [mailto:r-390-bounces at mailman.qth.net]On Behalf Of rbethman
> Sent: Monday, September 27, 2010 4:06 PM
> To: r-390 at mailman.qth.net
> Subject: Re: [R-390] saga cont pt 12
>
>
> 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
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