[R-390] saga cont pt 12

[ka9egw at britewerkz.com]

The ones I'm talking about [there's one on the primary side of the 16-32Mc
first can] are a little bigger around than a pencil lead.  I know it's a cap
'cuz the schematic tells me so, but it looks like a miniature version of a
VERY old resistor...
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 4:21 PM
To: r-390 at mailman.qth.net
Subject: Re: [R-390] saga cont pt 12


  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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