Filiberto investigated the TMSX issue (7675, 7676) and found a wrong cable had been used.
Now things are better, and there's a valid DC signal appearing, but there's still HF noise. Zooming out shows peaks at 1850 Hz and multiples (3700 Hz, 5550 Hz, signs of something at 7400 Hz), so something is presumably oscillating.
Filiberto tried various combinations of powering down the sat amps and swapping them and eventually got the 1850 Hz ringing to go away.
Found missing cables at vacuum mock feedthru panel. This cable is not a standard one to one pin, but is flipped on one end to simulate the in-vacuum feedthru. After this, Mark reported high frequency noise. Did different variations of powering off coil driver and satellite unit. Signals look stable.