[AMPS] AL-80b PROBLEM - ANY IDEAS?

[Tom Rauch]

> 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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