After powering up the FMy satellite boxes and checking that the EE on the outside of the chamber were functioning properly (thanks, Richard), I went in the chamber to look at the in-vacu stuff. Indeed, the cable that needed an end-to-end swap before the holiday break, had not finished making it to it's connecting octopus cable. When I tried to seat it, I found that the 225 cable needed helicoils, preventing good connection. We're hunting tools now to finish helicoiling these (all 3 225 cables need the helicoils) connectors.
Today I finished helicoiling and connecting the FMy cabling at the optical table. While this eliminated a possible source of problems, it turned out the real problem was a bent pin on the air side of the feedthrough. After straightening the bent pin, the cable was reconnected and successfully tested for functionality.