I have a Commander HF-2500 which uses a pair of 3CX800's. Recently I've
noticed the plate current does not drop back all the way to zero when
un-keying. The longer it's on and the hotter it gets, the higher this
current is. It starts out around 50 ma and after a half hour or so of
RTTY, will get up to 250-300 ma. If I let it sit with filaments on but
not keyed, eventually the current will drop down again.
I'm suspecting some out-gassing in one or both of the tubes. I know the
previous owner seriously overheated the tubes to the point where the
delrin insulators around the tubes were melted.
Does this sound like a bad tube or tubes?
Thanks in advance,
73, Bill W7TI
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