> on the plate. Turning the XMT switch on the AL-80B to STBY makes no
> difference. I have to turn off the linear in order to get things back
> to normal. Perhaps a failure in the AL-80B bias circuit? ALC
> voltage is set correctly, and grid and plate current are normal with
> key down just before the failure.
It could be many things.
Possible causes are a shorted bypass cap in the filament line,
anything on the filament side of the transformer center tap or a
wiring problem there. It's very unlikely or next to impossible to be a
relay problem, as long as the receive comes back up.
It could also be the tube. Some batches of Amperex tubes have
had a filament-grid problem.
73, Tom W8JI
W8JI@contesting.com
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