[EricS]

Morzh: i have a variac, but am not sure how best to use it in this context. Yes, the entire chassis has been recapped (new resistors, too), with the exception of the bakelite cap block at the AC input. The fuse is after the AC connection to the bakelite block, and since the fuse blows only when the power switch is turned on, I presume the bakelite block is OK. Bear with me a little bit here, I am not sure what you are asking me to do with respect to the rectifier tube. Using this diagram as a reference (http://frank.pocnet.net/sheets/021/8/84.pdf), is the filament voltage the voltage across pins 1 and 5 for the heater? If not, which pins are you referencing?

Using the same pinout image, I get the following voltages on the rectifier socket - tube removed and radio directly plugged into AC outlet:
Pins 1-5: 6.8 vac
Pins 2-4: 258 vac
Pins 3-4: 259 vac
Pins 2-3: 520 vac

Jerry: thank for the confirmation of the e-cap wiring. This was the part I was most unsure of. Polarity is confirmed for both caps. Measuring resistance from rectifier pin 4 (+ of 12 mfd to chassis) reveals 0.6 ohms after a it settles down. Removing the rectifier tube and measuring resistance across all pin combinations reveals resistances of 1 to 10 ohms. How can I tell if I've got a bad tube?

All of these readings are without the speaker and field coil connected. I connected the speaker cord after replacing the fuse and powered it on and the fuse blew again. I think I'll need to buy a few more packages of fuses...

Thanks for your help!
Eric