Admiral 20B1 Combo restoration

[Eric H]

I'm guessing a short also, possibly why the original resistor was overheating.

Backwards cap could do it but it would likely explode at some point so possibly something else is shorted or wired wrong.
Start disconnecting the B+ circuits one at a time and see where the short disappears.

I always take some high resolution digital pictures before I replace anything, that makes it easy to check for mistakes if things go wrong (and they always do!)