07-10-2017, 05:14 PM
Don't attempt to power up one of these without the field coil, or a substitute choke in place, or bad things will happen to some of the resistors around those tubes. Pulling the speaker does NOT kill the B+ to the entire radio, so whatever is still connected gets almost the full B+ from the power supply with the load of the power outputs removed. It's a design flaw really that Philco did not add a jumper on the speaker plug and socket to take care of this.
Regards
Arran
Regards
Arran