>
>> 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".
>
A not uncommon human failure is denial of reality.
>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!
>
Four AL-1500 owners have reported five or more sudden 8877 failures.
>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.
The welds that were breaking in late production Eimac 3-500Z/8008s would
not have earned passing marks in my sheet metal class. Sound spotwelds
are never perfectly smooth.
>
>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 know of a certain German-made xenon projection lamp that had to be
modified because it was found to be oscillating occasionally at c.
400MHz.
> I've even taken to ordering special nichrome lightbulbs just to be sure they
NEVER have
>an oscillation.
>
>
later, Tom
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