Collins Aerospace Museum

233D Transmitter Restoration Project

This Autotune unit couples the Power Output section to the antenna.
I had intended to get in this morning and finish the modulator bay, but I had a problem with my leg this morning and so I have to go back to PT for an “evaluation”. Problem is that we got carried away at the Y yesterday with 3 miles of walking and lots of stretching and I think I just stretched some underused muscles that resulted in one of the worst charlie horses I’ve ever had.

I am now planning to spend some time with the mod bay on Monday, if all goes well and then back on Wednesday, although I need to leave by not later than 12:15 or so. I’d like to have a really big get together on Feb 6 to involve as many potential volunteers as we can.

Rod took the RF final deck and Grid tuning assembly home and Wednesday and has made some significant progress on them. He has created some color pictorials of the assemblies with parts id’d. I am adding them to the 233D file and they will be put on the thumb drive.

Rod has suggested that we ask Larry Tjaden to create a web site for the project and store everything there and make it available for anyone interested in helping. I have not been successful in making contact with Larry, so some help in making that happen would be appreciated.

Also am still trying to get the cabinet photos to Mike Barton. An email to got kicked back and his old phone number comes up at no longer in service. I had intended to try to locate him today, but that will have to wait until Monday.

Also looks as though the chrome replating will be extremely expensive and take some time. I’m continuing to look at this but it has been suggested that powder coating may be able to approach the chrome look at considerable lower cost and may not require stripping the chassis. I think powder coating involves an electrolysis process but I doubt that we need to worry too much about ESD.

I am starting a list of shortages that we need to consider:

1. Rod found two ceramic posts that were damaged. 1/2” by 1.25 with 8-32 screws. I think I have some, but will need to find them.
2. Autotune drive shaft between exciter deck and PA deck. Rod thinks Don Grimm can do the machining if we proved a drawing. Nothing in the 233D package, and the 231D manual doesn’t identify it enough to provide a drawing number and I’m not sure it would be what we need anyway. Hopefully, the manuals in the archive will help. Absent that, we can likely fab something based on the section of shaft that we have. I had hoped that the missing shaft might be in one of the boxes, but haven’t found anything. Fairly sure it was not shown in the ebay photos, so guessing it is long gone.
3. Large glass in the Mod Bay and RF Bay doors missing. Expect it is the same size as used in the Power Bay.
4. RF Bay blower. Same PN as used in Mod Bay and Power Bay nothing was provided for the RF bay. So we either cut the existing panel and install a similar fan to the other bays or add a blower in the bottom of the cabinet. I don’t think there are any exhaust vents in the upper panels of the RF bay, so that would be an issue. Lawrence thinks we may have an HF-80 blower that could be used outside the cabinet, but we would still need to provide some sort of exhaust in the upper part of the cabinet. The 231D-20 had one big blower in one bay and then channeled air to the other two bays. Doubt that cooling will be a major problem as long as duty cycle is low, but the 450TL and 813 filaments alone will generated some heat that needs to get out. Likely be a simple solution but will require some major surgery.

Rod thinks we will need a fair amount of DeOxit for the switch contacts in the RF deck and we will need to use some on all the “19 Pin” connector that mate the chassis to the rack connectors. Probably need a couple of cans from Iowa Radio. Rod thinks about $12 a can which I think may be low. Radio Shack sells pairs of DeOxit and Caig Gold for about that price, but the cans are really small. Maybe engineering stock rooms have it? Not for free, but as a personal sale. I bought some stuff from main plant stockroom when I was on contract, but I think it required an on line order.

I don’t have Larry Tjaden and Mike Wilson’s email addresses. Appreciate it if someone to can add them to the list so we could inform them of what we are doing. Goal is to really get things moving on February 6th. Think I’ll plan to start bringing in my laptop. I assume they will let me in and out with it. Had some problems with computers years ago; almost went to jail because I took a Grid to a customer demo and the guards got confused even though I had all the proper paper work.