Collins Aerospace Museum

233D Transmitter Restoration Project

I have connected the 208 single phase to each of the big plate transformer primary windings and got output as shown on the attached image. About 3400 VAC.

Three phase has been wired to the power contactor and everything appears to be good up through the big circuit breaker, but I haven’t got the contactors figured out yet. The contactor labeled as the one used to switch the plate voltage is actually the one used to add resistors used for test mode. I had expected that I would be able to manually select plate voltage on mode and test mode, but that does not appear to be the case.

The “B” leg output to the cabinet assembly that should be on terminal 14 of the connector field is actually connected to terminal 3. Needs investigation.

The test mode resistors that were in series with the three phase legs on the TDH-2 and 231D-12 appear to be added as shunts on the 233D. More investigation needed.

I have started using colored highlighters to track the power distribution. Lots of switches and relay contacts make navigation difficult.

Installed new isolators on the big filament relay on the power control chassis, so it should be ready to put in the rack. The power control assembly is the “brains” of the power system, so having it working is essential to getting things going.

Good news is that the plate transformer appears to be in good shape. Initial current surges up to just under 2 amps, but then settles to a couple of hundred mils and no noise at all.

I had thought it would be a good idea to remove the big transformer from the case, but there are two large angle irons that are welded into the cast to retain the transformer. Considering the fact that the transformer weighs 600 pounds, I elected to concentrate the exterior cosmetics and, since it appears to be working properly, there is no need to do the removal.

Mike Hynek will come some days at lunch to help keep me on track and to shut down the power if I do something really stupid.