> You asked for an example ... I gave you one that repeated itself.
> I am curious as to why I had to replace two 3-500z"s. The way the
> amplifier made a huge grunt and tripped the breaker ... with the 3-500Z's
> shorting and pieces of either filament or grid being loose in the tube
> tells me something violent happened. And since it occurred while moving
> the top cover in relation to the tubes and tank circuit, leads me to
> believe it was an oscillation. What is your expert explanation please ?
Don't know. There could be several causes.
Isn't the Henry interlocked? Did you accidentally short the HV to
ground?
Coincidence is often not a reliable form of analysis. My sister-in-
law lost two husbands, each time after moving into a house whose
street number totalled 9 at the end. You'll never convince he that
cancer isn't caused by house numbers.
> >>2.) What type of tubes.
>
> HELLO !!! Already stated.
DUHHH!!! What manufacturer. Do you understand that better?
> >>3.) Why don't the photons generated in normal operation cause the
> >>same problem?
>
> You asking me ?
Yes. I generally like to know if a theory is even remotely
reasonable before believing it. The "photon theory" is rubbish,
unless photons in California are different than photons in the rest of
the Universe.
> >>4.) Why don't photons in gas-filled tubes specifically designed to
> >>detect photons have even modest amounts of current?
>
> >>5.) Why do hundreds of other amplifiers without covers not fail?
>
> ??? Has nothing to do with what I stated.
It has everything to do with what you stated, because you offered
your "story" in support of Measure's claim that a photon can cause
a tube to suddenly draw so much current it with cause the relay to
arc and put the PA in an operate position.
If that was true, why are radiation detectors optimized for this
purpose filled with gas, and why do they have peak currents
millions of times less than the current in a power grid vacuum tube?
If that made sense, why do many or all amplifiers with tube arc
when exposed to room light? Why can't we use 3-500Z's as
photocells?
> >>6.) Since the saturated current of a 3-500Z is about 10 amperes or so
> >>(that's all the filament can "give up", even if you hold the anode and
> >>grid at 3000 volts positive), how does the oscillation cause enough
> >>current to shatter the filament or grid?
>
> I would really like to know what shattered mine.
Well one thing we do know, it can't be anode current through any
kind of emission.
Maybe you simply moved the PA, and the filaments were ready to
break.
> >>7.) If the tube could supply that much current, how does it get that
> >>current so fast through the high surge impedance of the path from the
> >>energy storage area (power supply) into the tube?
>
> Good question ... but in this case as I recall there is no current
> limiting in the B+ or B- of the HV supply.
Use logic. These alleged "gremlins" are all VHF parasitics.
The reactance of the anode choke and even the leads inside the
PA would severely limit the current. The only major current that
could flow, assuming Henry didn't design-in enough ESR to limit
surge would be at dc and through an arc that actually sustained
high levels of conduction for a long period.
I think someone has a parasitic fetish.
> >>If you have no explanation other than blind faith, then I can accept
> >>that and respect it. I never argue religion.
>
> I have no explanation, only suspect.
OK, then I can accept the fact you have no idea what caused the
problem. Only a guess.
Unfortunately facts about how things work don't support such a
guess.
73, Tom W8JI
w8ji@contesting.com
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