I was investigating several issues on the IFO. As many of you noticed and not elogged, ITMX had frequent kicking without its oplev servo.
Also I had C1:LSC-TRY_OUT flatted out to zero even though I could see some fringes C1:SUS-ETMY_TRY_OUT.
Restarted all of the realtime models (no machine reboot).
Now I don't find any beam on REFL/AS/POP cameras.
If I look at BS-PRM camera, I can see big scattering, the beam is in the BS chamber.
I jiggled TT1 but cannot find neither a Michelson fringe nor POP beam.
So far I can't figure out what has happened but I'm leaving the lab now.
IMC is locked fine.
I can see some higher order mode of the Yarm green, so the Y arm alignment is no so far from the correct one.