Responding to Daniel's report of issues with the ISS and FSS, I came in this morning to see what's up.

I found the NPRO was in a large relaxation oscillation (frequency about 880 kHz) (see photo below) by displaying the ISS PDA signal at the monitor tee (see photo below) on an oscilloscope.

This was cured by toggling the "Noise Eater" switch (off for a few seconds, then back on) on the front of the Innolight power supply in the PSL rack outside the Laser Area Enclosure (see photos below).

I adjusted the ISS REFSIGNAL to -2.00 V, which gives us about 10% diffracted light (see photo below).

I looked at the FSS OLTF and found the UGF to be about 500 kHz.  I dropped the common gain by 3 dB (from 30 to 27) to give us a bit more gain margin and a little more phase margin.  The UGF is now at about 325 kHz.

The system seems to working properly now.