This afternoon, the ITMX ISI tripped, was continuously glitching and couldn't be recovered. Even when I put the ISI and HEPI in non-actuating states the ISI continued to get glitches that almost saturated the seismometers. Fil went out to the rack and while I watched the ISI he turned off the coil drivers one at a time. It wasn't until he turned off the third coil driver that the glitching stopped and the ISI started behaving normally. This is exactly the same as the event in July, where I found the St2 H3 sensor seemed to be mis-behaving. Looking at the current and voltage mons, it seems the St2 H3 coil was again misbehaving, attached trend shows the st2 coil voltage and current mons. The only outliers are the St2 H3 channels, this window should be during a time when the ISI masterswitch was off, the drives should be ~0.

We should pull the corner 3 coil drive at the next opportunity. I think we have a spare in the EE shop.