[Collins] Top hat power diodes

[Dr. Gerald N. Johnson]

On Fri, 2008-05-23 at 11:26 -0500, stbradford wrote:
> While reviewing some photographs of past repairs to my 1962 S Line, I
> noticed the original top hat diodes were still in the receiver and power
> supply for the transmitter. The question is, "is there any valid reason
> to replace them"?
> 
> I am not one to fix what "ain't broken"....but they are at least 46
> years old.
> 
> Smith Bradford
> W9HAK
> 
There is no gradual degradation mechanism in silicon diodes so there is
no need to replace them unless something like a voltage transient or bad
electrolytic causes them to fail.

The modern 1N4007 specifications have a greater reverse voltage rating
and a more controlled reverse breakdown characteristic and a higher
current rating. Whether the imported parts will meet their
specifications may be a question for test, but the thoroughly tested
part may not survive the tests even if it meets the part specifications.


-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer