This morning, Arnaud mentioned that 2 of the 14 OSEM signals on SR3 were completely open light. To which, Travis and I leaned in and said "excuse me, what??" Apon trending and attempting to actuat, Arnaud found no life on the suspect 2 OSEMs/magnets on the M2 (Intermediate) stage of the SR3. This screams broken magnets to us, however we cannot inspect becuase the doors are still on the chamber. Arnaud will append trends and details of when it happened below, but we will add to the LONG vent list to fix these in-situ. Note, the HLTS intermediate EQ stop design is very BAD (see attached pix). The bottom EQ stops of the intermediate mass are pretty much inaccessible - they can only be accessed via sticking your hand through the optic below. Tools do not help. Likely the lower EQ stops were not set close enough to the mass. (Ignore the red circle in the first picture - it highlights a whole different problem. The inaccessible EQ stops are in the green circle on the 2nd picture.)
On may 28th, UR and LL M2 osems signals changed from ~13000 cts (nominal value when flag is centered) to their open light values (~25000cts), see attached screenshot
Several tests were tried, and they all confirm that the magnets are probably off :
1. Sent an offset in L to the top mass of suspension to pull the masses, expecting the osem signals to decrease. UL and LR osems decreased by ~7000cts UR and LL didn't change.
2. Sent a drive sinusoidal signal at the first pitch mode frequency (0.65Hz, 100000cts) in each of the osems, expecting the test mass to respond in pitch at the same frequency.
M2 UL drive : M3 responding
M2 LL drive : M3 not responding
M2 UR drive : M3 not responding
M2 LR drive : M3 responding
