----- Original Message -----
From: Tom Rauch <w8ji@contesting.com>
To: <amps@contesting.com>; Carl Clawson <ws7l@arrl.net>
Sent: Sunday, March 05, 2000 4:39 AM
Subject: Re: [AMPS] Re: Poor science
>
> Hi Carl,
>
snip
>
> Better yet, give me an example where the oscillation suddenly
> occurs in a PA that operates normally under all sorts of loading
> and tuning conditions for many years, and where that same
> oscillation shows up as a sudden explosion while the amplifier is
> on standby.
>
> Rich claims that can occur. Perhaps you can site an example that
> doesn't fly in the face of good science.
>
> > I'll come up an example or two if you'd like.
>
> I'd like. Specifically, tell me how a tube that is otherwise healthy
> can suddenly draw hundreds of amperes...or that can hold off ten
> or 12 kV can suddenly arc from these sinister parasitics that lurk in
> virtually every non-nichrome PA in the world.
I really question why I am wasting my time with this ... I hope this will be
of interst to some ... I am sure Mr. Denial will will just consider it
nonsence as he has with most all of Rich's claims ... But this is from the
real world of what actually happens ....
The amplifier was in STANDBY ..... NOT KEYED .... but with all voltages ON !
I had a reason to remove the top cover (high voltage interlock removed), I
slowly raised the cover from the front of the amplifier leaving the rear of
the cover sitting on the amplifier ... when I got the front of the cover
raised about 3 inches ... all of a sudden the amp made this huge big grunt
and the circuit breaker tripped off. After I removed the top cover and
turned the amp back on I had idling plate current in the standby mode. Long
story short ... I had one of the two 3-500Z's with a grid to filament short
and that tube had metal particles rolling around inside of it. Ten minutes
earlier this amp was putting out 1300 watts on 20 meters. NOT knowing what
had happened I replaced the bad tube and tried again. Guess what ... with
the cover about 3 inches raised ... yes ... I lost another 3-500Z ! This was
a damn expensive way of being introduced to the type of oscillation that Mr.
Denial says can't happen !
Terry W6RU
--
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
|