J. Kissel

I've recovered FULL ISOLATION on the SEI system at the end station, as well as damped all the SUS. While watching/waiting for the ISI to isolate, I noticed that H1 SUS ETMY's M0 L damping loop output was consistently rather large (was +/- ~700 [ct], where it's normally +/- 1 [ct]). Pulled open a dataveiwer trace, and found the main chain ringing at ~5 [Hz] with consistent amplitude in L. Grabbed a few "quick" spectra in DTT, narrowed down the frequency and to demonstrate the problem for this aLOG....

... and the problem disappeared. I turned on the L, P and Y damping loops after just getting enough data for the "V T R damping loops ON, L P Y damping loops OFF" measurement. And no 5 [Hz] oscillation. All DOF's damping outputs restored to just barely above 1 [ct]. *sigh*

So I'll leave the title up to gather enough attention such that a little forensics can be done, but at least the SEI / SUS at EY pass these superficial, tired Jeff, tests (isolating the SEI system and turning on the damping loops for the SUS).

As mentioned in LHO aLOG 18518, I'm going to come in early again and measure H1 SUS ETMY's AI chassis, but I'll leave the SEI/SUS system in its up-and-running state overnight before I attack.