J. Kissel, P. Thomas, E. Hall, K. Izumi, E. Merilh

We had ceased calibration activities around 10p this evening, and have been trying to recover the interometer since. A few things that have bitten us that none of our current systems could have caught:
(1) Kiwamu had turned ON the frequency servo for the ALS DIFF PLL while tuning ALS DIFF actuation function measurements. This was left ON when he was finished, so it took Patrick and Kiwamu a bit off tail chasing witht the VCO frequency slider when the ALS DIFF guardian couldn't find IR. 
(2) Once we got past ALS DIFF onto to DRMI locking, we immediately saw the normalized ASAIR B RF 90 purple trace on the PRMIsb.stp was high. Kiwamu found that this was a result of new large dark offsets on the electornics. We suspect this has to do with the "transparent" work done in the HAM6 Racks today (see LHo aLOG 20838).
(3) An initial alignment was needed (no surprise).
(4) Something went wrong with what Evan suspects to be offloading just before the CARM offset reduction. This reduced the recycling gains by a third, and made the signals very noisey. Somehow the lock acquisition sequence and CARM reduction managed to survive, and eventually the SRC and SRC cavity signals came back to normal. Huh... we'll see it if repeats. 
(5) Power normalization didn't work during power up. Guardian skipped to COIL_DRIVERS without completing INCREASE_POWER.
(6) repeat of (4) ... ifo makes it again though. Kiwamu later identifies it as a problem with SRM alignment
(7) Fail at the ETMY transition. Found it due to ETMY being still in its high-voltage setting, left over from the later work that Kiwamu was doing with ALS DIFF.
(8) Fail at PRM low-noise noise transition (3 coils is less stable to coil driver switching than 4 coils). Hopefully this'll be fixed tomorrow.
(9) This SRM alignment business is getting better, without us doing anything...
(10) repeat of (5), Evan now suspects an ISC_LOCK guardian change he made yesterday...

I'm running out of steam for this. I'll leave it to others to document the rest of the recovery, 'cause this is gunna be just as hard if not harder tomorrow... 
#premaintenanceday