I've taken out the selenium rectifier and replaced it with a single diode. I've also installed 3 new electrolytics in place of the filter cap.

There is a dropping resistor immediately after the diode. When I apply power this glows red hot and eventually cracks in half, shorted it would seem.

I'm trying to retrace my connections as shown in the schematic but I can't find what I'm overlooking. I am merely an aspiring tube radio technician & this is my first true test!

Anyone have any hints for me?

Did the set work prior to the selenium rectifier/filter cap replacement?

If it did, I would suspect that you inadvertently reverse-connected at least one of the electrolytic filter caps; or perhaps created a solder splash short-circuit from B+ to ground in the course of doing the repair work.

If the set didn't function prior to your work on it, and you are certain that the new caps are correctly installed, you might check each tube for the correct number and that it is installed in the proper socket.

:Did the set work prior to the selenium rectifier/filter cap replacement?

Yes it did work, although it had some issues of course - the main one being AC hum.
Thanks for the tip. I'll focus my troubleshooting on the new capacitor bank.

::Did the set work prior to the selenium rectifier/filter cap replacement?
:
:Yes it did work, although it had some issues of course - the main one being AC hum.
:Thanks for the tip. I'll focus my troubleshooting on the new capacitor bank.
:
:
Hi Dave,
The dropping resistor in series with the diode needs to be at least 2 watts. If it were replaced with a lower wattage resistor, it will burn up.
I am unfamiliar with K731, but I restore Zenith H723's often. Their resistors are 22 ohm 2 watt. When a silicone diode is used as a replacement for the Selenium I replace the 22 ohm 2 watt resistor with a 60 ohm 5 watt resistor (calculations show a 3 watt will do).
Yours may need a higher wattage dropping resistor.

Best regards,

Bill Grimm