[codefox1]

Well, this looks like it's gonna take some time and patience. It's rare to have a new capacitor defective; but it happens now and again. You might want to take the coupling capacitor to the 50L6 out and sub a new one. The other thing that happens now and again is then there is a lot of crud inside the IF cans and a short occurs, that will bring the B+ down, but usually with some clues like heat, smoke, and drippings. If you have blasted these out with deoxit and allowed to dry overnight, rule this out.

Measure the current consumed in each stage by inserting a dc ammeter and you will find where the problem is. If you have any doubts about the field coil/speaker/output transformer, sub a resistor for the field coil, and run a known good output transformer and PM speaker to test it out. Don't worry about values so much, 500 ohms for the field coil sub, and just about any generic output transformer and speaker should work OK. Just keep an eye open for the load on the B+, and shut down if it gets too high. Again, the current draw against B+ will be your guide.

If you have a variac, you can proceed at a more liesurely pace.

Just one thing more, sometimes the crappy tube sockets on some of these sets develop an arc trace. Cleaning them will not cure the problem. You might have to replace the tube sockets for the 50L6 and/or the rectifier tube. They both get real hot, and the unmentionable pollutants over the years within the set ultimately create "current sinks."

You're getting close to solving this one. Let us know!