Mark,
The plate choke looks to have a bunch of corona dope or black silicone
adhesive around its base. I would say there has been an arcing problem
here. More than likely, the windings on the choke were loose and they
added the adhesive to keep them in place. Whey they put it on the top of
the blocking capacitors is beyond me. The parasitic suppressors have
been replaced also. By the looks from everything, parasitics have been
what's caused all the problems of the arcing. That amp has been
"retired" and the HV power supply used for something else. Your looking
at a lot of cleaning to get it back to where it once was. Besides,
without looking underneath the chassis, I'm afraid what might be there
too! The tank coils should be cleaned with a tarnish remover, then
sprayed with a polyurethane varnish to prevent corrosion. The tune and
load caps should be cleaned well also. Especially where the wiper meets
the plates. It looks like it was once blower cooled with chimneys. The
chimney clips are still there by the looks of it. If not, a big fan is
needed to blow directly on the tube envelopes. Fan cooling is necessary
underneath to keep the tube pins cool too. Last, make up a new set of
parasitic suppressors for the tube anodes. Finally, there's no way of
telling how good those tubes are. In the end, I wouldn't spend very much
on this item, maybe $100 at the most.
Will Matney
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