• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Heater circuit on Bell RP-320 preamp

I pried it open, cleaned it out, replaced the caps, and rolled the edge back over. Does it look factory? No. Can you tell after it's installed? Who's looking that closely? 😉

The big concern at this point is the apparently toasted transformer. 🙁
 
The big concern at this point is the apparently toasted transformer.

Perhaps Heyboer can wind you an "exact" replacement.

OTOH, if simple functionality is the objective, you could rework the entire PSU to use regulated 12 VDC on the 12A_7 heaters and whatever (SS or vacuum rectification) that gets you the "raw" 320 VDC feed for the OEM B+ filter. Antek's AS-05TC250 could work out for you. Phased up and operated in parallel, the 2X 6.3 VAC windings have plenty of current to feed both a "full wave" voltage doubled 12 VDC heater supply and the OEM pilot lamp. SS rectifying the 2X 250 VAC windings would get you the requisite "raw" B+.