[Amps] New GS-35B amplifier..

[Bill, W6WRT]

ORIGINAL MESSAGE:

On Sun, 12 Apr 2009 12:09:41 +1000, robert briggs <vk3zl at bigpond.com>
wrote:

>I am wondering if I have a bad tube or is something else breaking down 
>in the output network somewhere...Maybe someone may have some ideas....

REPLY:

It sounds like something is breaking down somewhere. I had a similar
problem once that turned out to be the little RF choke which is placed
across the output of the pi-net for safety purposes. It was arcing at
anything above about 200 watts in my case. You can temporarily just
disconnect it for test purposes. Be sure to reconnect it when you're
done. :-)

Another similar problem I had once was a defective vacuum variable
cap. You didn't say if you are using vacuum caps or not, but if one
develops a small leak, it can cause the symptoms you are having. It
appe4ars to work ok at low power but as the voltage increases, at some
point the gas ionizes and becomes conductive. A hi-pot tester should
reveal the problem if that's what it is. 

In fact, you can hi-pot test the entire pi-net tank after
disconnecting the above mentioned RF choke, of course.

73, Bill W6WRT