[Electronic M]

Most pots are obtainable or can be cobbled together(IIRC Mark Opatt specializes in recreating vintage controls)...if it is a rheostat (wire wound resistor based pot) that can get tricky. Most sets used rheostats for vertical centering, but RCA around that time used carbon comp pots in places you'd expect rheostats so anything is possible.

Vertical output transformers and most sweep transformers are usually hard to find for most sets. You might find one (might take a LONG time), but don't count on it.

There are companies that can wind transformers to spec, and home rewinding is possible (I once did it on a Zenith monochrome vertical output), but they are expensive and tedious respectively.

If you already paid for it then in your shoes I'd trace the fault down and test the parts for correct resistance and confirm they failed before trying to source them.

That bang you heard could be a very wide variety of things. Could be something as simple as the ground and B+ shorting together from a poorly routed replacement cap lead.