I was working on a similar problem in an old vacuum tube radio during my
lunch hour many years ago. I had a signal on the grid,proper voltages on
the electrodes, and no output with a good tube. I was measuring at the
socket terminals. An experienced technician friend suggested that maybe
the socket contact had lost its spring action and was not actually
making contact with the tube pin. He proved to be right. Never overlook
the possibility that a tube or connector pin has no continuity to its
mating part.
73, Dan, N5AR
carl seyersdahl wrote:
>
> this is not exactly relevant to hi-power, but many years ago, when I was a
> young technician(way back there)I had a problem like that, with an audio amp
> stage. This was a 6AQ5 amplifier. It was doing the same thing, running away
> after about 15-20 seconds. all the new tubes in supply did the same thing,
> and as I recall no one ever found the answer, and it was looked at by many,
> many technicians. To this day I don't think anyone knows the whole answer.
> Just one of my fuzzy memories!!! carl / kz5ca
>
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