[Amps] Ameritron AL-80A

[k3air at stargate.net]

Hi gang,

I'm a newbie when it comes to working on amps and would like some
suggestions/advice.  Here's the situation:

I recently acquired an AL-80A which appears to be cosmetically good and
complete.  When I fired it up, the plate and grid current appear to be
fine.  However, the plate doesn't "dip" and applying any significant drive
to the amp results in "hissing" or "sparking" noises and of course zero
power out.

Any ideas as to what may be wrong and where to start?

73, Mike K3AIR