This morning Fil swapped the ISC common chassis at end X and end Y. This was followed by some problems at EX (broken module and/or terminal?), which was later fixed this afternoon by Daniel Marc and Fil.

Looking at the usual magnetometers and the ESD power monitors it's clear that the noise did not move with the chassis: We still see a broad ~94Hz lump at EX, see fig 1 & 2 (previous investigations in this thread) and sidebands at EY, see fig 3 (preivous investigations in this thread).

This is surprising - we thought that the chassis was generating the noise and polluting the ground, and that the noise would move with the chassis.

There is some additional noise in the EY ESD power monitors, including a wandering line at ~81 Hz in red. I think this is unrelated to the chassis swap. Ansel noticed that the EY power monitor got noisy sometime on Sunday night.

The summary pages show the end station magnetometers during the switch. It looks like from ~16:20 to 22:15 the EX ISC common chassis was off/broken. During this time there is some weird noise in the EY magnetometer, but as far as I know that chassis was installed and powered on quickly. The EX SEIRACK magnetometer also shows some weird noise, but I think that one is out of action.