Collins Aerospace Museum

233D Transmitter Restoration Project

Jules noticed that the new channel switch wafers are indexed about 90 degrees off the old wafers. Not a big deal; just have to make sure the crystal select position is properly synched to the 837 suppressor grid voltage divider and the Autotune channel selected pin. Good catch, Jules!

We also need to bring out a pendant cable from the 807 screen to make sure the exciter band switch is selecting the proper position. Don’t think we need to use another breakout, but can probably add another socket on the “optional” 813 plate voltage divider network. I’ll work on that next week. We will be able to use that circuit to either measure screen voltage when power is applied or resistance when it’s not.


Additional comment.
The good news is that the switch shaft that rotates this switch is perfectly square meaning that the replacement wafer can be installed in one of four rotor positions. As Jim pointed out the new switch replacement is 90 degrees displaced from the original. This means the the wire harnes bundle going to the switch is only displaced by a few degrees physically on connecting the wires to the switch by selecting the closest rotor position that matches the original on switch reassembly.