[AMPS] 2nd harmonic pumped parasitic

[Tom Rauch]

> What intrigues me, is that certain amps appear to work for a while, even
> in hygienic surroundings, then suddenly say "good bye", apparently without
> good reason. But your reference to the effect of reactance on oscillation
> might be the clue, especially when one reads reports about deteriorating
> connectors and water running onto Joe's feet down the coax...
> 
> Cheers,
> Ian ZS6BTE

We have a engineering term for that in the USA Ian, it's called 
"component failure".

I know people expect parts, especially tubes, to last for hundreds  
of years and never fail....but sometimes a random failure actually 
does occur and even more strange it is not for any sinister reason!

At times power transformers have insulation failures, occasionally 
electrolytics open up or short, resistors fail, and quite often tubes 
have internals that outgas or have leads that break or welds that 
just fail from fatigue in normal operation and ruin the tube.

I know it sounds weird and totally unbelievable, but I've even seen 
light bulbs fail and...... as unbelievable as it is....... they didn't 
seem to have a parasitic oscillations! I've even taken to ordering 
special nichrome lightbulbs just to be sure they NEVER have an 
oscillation.




73, Tom W8JI
w8ji@contesting.com

--
FAQ on WWW:               http://www.contesting.com/ampsfaq.html
Submissions:              amps@contesting.com
Administrative requests:  amps-REQUEST@contesting.com
Problems:                 owner-amps@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm