Today TJ had the IMC locked without the IFO (with the ISS first loop) from 18:45- 22:45, without the IMC losing lock.  This might suggest that the change of the FSS EOM path op amp yesterday 81247 did indeed solve the issue that was making the IMC unstable even without the interferometer locking, but more time would make this a more definitive test. 

During the 4 hours Jason and Marc also went to the floor and measured the FSS OLG, 81254, which showed some places where there are mulitple places where it came close to unity gain.  They lowered the gain by 0.75 dB.  Later, Marc and I went and measured the IMC OLG, and we tried lowering the gain by 3dB (common gain of 12dB), to give the FSS OLG more clearance from unity gain, we measured the IMC OLG before and after this change 81259. 

We decided to try locking tonight with the FSS gain at 12dB.  If the interferometer is not stable through the evening shift, Corey will set the IFO to down and leave the IMC locked overnight so that we can get more time for the test of IMC stability on it's own.