I was in the lab, near the south end of the ITMX oplev table, looking for something, and I bumped the POP ASC QPD's power supply.  I thought that it was fine, but did not adequately check it.  When EricQ asked me just now about why the PRC is so wobbly today, I checked, and the power for the QPD wasn't properly connected (it's kind of a crappy connector, that if you nudge, contacts or loses contact).  Anyhow, I restored power to the QPD, and the PRC looks a little more stable now.  My fault for not checking more carefully, and my apologies to Q and Gabriele for their frustrations this afternoon.