Well, the manufacturer and part numbers are on the mating connectors, so one can tell what they are directly. They are both Sealectro (which is what the OP wrote) with different part numbers for each half. I can see the part numbers, but I can't read them. I'll need to find a magnifier. They are not Lemo connectors.

I don't see the usual Tektronix-to-actual manufacturer list in the manual, and the manual is a bit confusing. I have been trying to decipher it. The Sealectro connectors seem to be called out as single-conductor connectors (item ref. no. 37), but that can't be right. It is shown on the schematic (J60) and shown as a three-pin round connector.

I'm confused. I also have one eye temporarily out of commission,so that is not helping matters.

DaveD