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[AMPS] Self oscillation with homebrew 3-1000Z ????

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Subject: [AMPS] Self oscillation with homebrew 3-1000Z ????
From: JimMoci@aol.com (JimMoci@aol.com)
Date: Sun, 6 May 2001 16:11:38 EDT
A problem for all the experts-
I Built a 3-1000Z monoband amp for 10 meters.  I Sowly Variaced it up and it 
seems ok at 1500volts. Put 3KV on it and it will make a few watts of power 
without even putting RF to it. I heard a small RF type arc- kind of like 
slight arcing in an air variable, (I have a vaccum cap) the tube glowed red 
and I quickly unkeyed it. I turned the load and tune caps a bit, tried it 
again- it was quiet for about 2 or 3 seconds- then it did it again. I have a 
similar homebrew grounded grid 4-1000A amp and never had a problem- it worked 
great the first time I fired it up! I built the 10 meter mono-bander because 
I cant get the 4-1000A amp to work on to good on ten- but it works great on 
the other bands. Any suggestions?? Keep in mind- I have yet to even hook a 
rig to this- just a dummy load- I variaced it up, saw idling current, and it 
started to run away.
Thanks!
Jim

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