Sheila, TVo, Georgia, Craig, Danny

• Last night as well as today we saw that there is a slow (~60 second period) oscillation of PRC1Y (AC coupled QPD to PRM), which seems to be fighting the dither loop.  We tried to turn off the PRC1Y twice, leaving the dither loop on, and both times an instability rang up in CSOFT P at 0.5 Hz.  Tonight we reduced the gain of CSOFT P by 20dB, and the oscillation went away. We were then able to turn off PRC1Y, and the low frequency oscillation is also gone. 
• Georgia added 10dB of gain to the YAW3 dither loop (which is for PRM), which she is putting in the guardian. 
• TVo and I saw that the X QPD combination used for the CSOFT P loop wasn't orthogonal to the CHARD combo, which we think it should be.  We put the matrix that is orthogonal to CHARD in CSOFT P A, and switched to that (0.111 for XA, 0.159 for XB, and 0.039 for Y B).  We increased the CSOFT P gain, and saw something ring up at 0.5 Hz again. 
• We sat with the CSOFT P gain low for about a half hour again, before something rang up at 0.5 Hz again, most visible in CHARD Y.  We increased the gain of CHARD Y by a factor of 2, and this made the oscillation go away.  With the CHARD Y gain increased, we could again increase the CSOFT P gain back to normal without anything ringing up. 

This current ASC situation seems better than what we've had the last several days, so we probably want to make some of these changes permanent, but we don't want to make any changes in the guardian since ASC engagement has been tricky and we may not have a chance to test things. I think that turning off PRC1Y, and increasing the CHARDY gain from 3 to 6 are definitely improvements.  The change to the CSOFT input matrix I'm not so sure about.