Identify a part?

[radiotvnut]

Some other thoughts: I can see that's a Zenith chassis. Those sets have one side of the AC line connected directly to the metal chassis. When the set is plugged in, there is a 50/50 chance that the hot side of the line is connected to the chassis. If you touch the chassis while another part of your body has a path to ground, you will receive an electric shock, possibly lethal! It's best to plug these type sets into an isolation transformer for service. This will greatly reduce the shock hazard while working on these sets.

You'll also be better off replacing that selenium rectifier with a modern silicon rectifier. Something like a 1N4007 should work fine. You'll need to place a resistor ahead of the new diode (between the AC input and the anode end of the diode). A 68 ohm, 5 watt resistor should work. The reason for the resistor is because there is less voltage drop across a silicon diode than there is across the selenium. Those old selenium's would short and give off a foul odor. I've also seen them become weak and the B+ voltage would be low.