There is definitely orientation on 300b's, 2A3's, & 45's, two of the pins are thicker. There should be a small pin or dimple on the socket, between the holes, where the thick pins go. Another thing you could try is heating the hole on the bottom of each tube pin with a soldering iron, while applying just a touch of solder. You could have a cold solder joint, and one of the wires lost contact. I think I have a pair of old school ceramic sockets if you want to swap them out.