Corey, Jeff, Jenne, Kiwamu,

Apart from the violin issues, we experienced two issues in locking the interferometer yesterday.

• The ASC SRC2 loops (a.k.a. the SRC pointing loops using ASC-AS_C) ran away multiple times.
  • This seemed to be due to saturation in the AS_C QPD caused by the violin modes.
  • Once Jeff and Corey damped them to the level where the AS_C QPD didn't saturate, Jenne and I were able to close the SRC2 loop without any issues.
• The DC readout transition failed several times.
  • This was also observed early in this week (37467). We still don't know why it kept failing.
  • More confusingly, it never failed today even though we didn't change any settings. This might be somehow due to the high violin modes that are now much lower today.
  • Jenne took a look at the spectra of AS_RF45_Q and DC readout signals from a past successful transition. They turned out to be almost identical (to our eyes) to those we currently see. So there are no issues in the sensing side.
  • We once went through the matrix ramping manually, by ramping them to a couple of intermediate matrix values. This worked fine although we are not sure what this means.