Lockloss @ 16:12 UTC - 5:39 into lock stretch. PMC unlocked, not sure why.

When trying to relock it, the signal on the locking PD would produce flashes, but not below the locking threshold of 0.15 (recall that Jason had recently raised this threshold after troubleshooting a similar instance of the PMC not being able to lock, which is why I find this behavior suspicious). Attached are scopes from my first three unsuccessful PMC lock attempts, where the flashes on the locking PD do not reach the threshold. After taking a few minutes to look at other things, I tried once more to lock the PMC, and this time it worked. See the fourth screenshot for the successful PMC lock, where the flashes do not reach threshold for a few seconds, then do. I then needed to pause the LASER_PWR and PSL_FSS guardians so the ISS autolocker wouldn't turn on by itself while I tried to lock the reference cavity. Frustratingly, several times the correct 00 mode would catch on the RefCav Trans camera and the PMC would unlock, but eventually it caught and the FSS was locked. I then turned the ISS autolocker back on and resumed the guardians.

I proceeded to start relocking H1 now that the full PSL was recovered. While locking ALS, the PMC mysteriously unlocked again and I had to repeat the process of relocking it, the FSS, and ISS gradually as described above. Strange.

After starting to relock a second time, I noticed the ALSX laser PLL was not locked. I manually set the crystal frequency to -100 MHz and after several seconds it had relocked.

H1 is now back to relocking, currently working on acquiring DRMI.