[R-390] Z503 Replacement

[Flowertime01 at wmconnect.com]

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>