Given that we have no laser light, confirmed by images of the PSL and cameras looking into HAM2, I set the PSL ISS Second Loop Array QPD dark offsets.  I accepted the values into SDF, and also had to accept the offset switch being on for all 4 segments, and I've confirmed that these offsets were zero in Feb 2017, during O2.

OFFSETS: Seg1 = 0.180, Seg2 = 0.180, Seg3 = 1.540, Seg4 = 2.370, and the SUM, which had been at +4.2, is now oscillating around zero.

I put an offset of -2.0 on the SUM to prevent it from going negative.  I tried using -1.0, but the pitch and yaw signals were still occasionally railing +/-32K.  The SUM during Feb 2017 reached 60K counts, so an offset of -2.0 is small.

Changes are recorded in the attached screenshot:  Left side shows current settings, rich side shows a snapshot of the QPD segment settings as found (zeros).