[R-390] Z503 Replacement

[Stephen M. Murphy]

That's what I was wondering, whether it is a manufacturing defect or an 
upstream failure causing the problem, since these things typically don't 
(can't) just fail on their own.  I'm also wondering if it's an "across 
the board" problem, or just affects those radios that were subjected to 
outdoor storage.


73-

Steve

On 04/03/2011 09:21 PM, Flowertime01 at wmconnect.com wrote:
> Just curious: Is it known what causes this inductor to open-up?
>
> -Steve N8NM
>
> Steve, in almost every wound wire case it is some small defect in the wire.
> The defect causes a concentrated current point. This translates to a hot
> spot. (very small) Over time it causes more burn and wire harding. This is
> higher resistance at the spot. In time the wire fails open. Eventually every
> coil in use will fail at its weakest most imperfect point. Some coils are near
> perfect and defect free so may not fail for several thousand years.
>
> Just look at the wire wrong between the wire drawing process and when you
> get the finished product and you can have a wire nick or kink. Any left over
> impurity from the smelting process and you had a defect.
>
> Roger</HTML>
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