Today when I tried to adjust the matrix of the PR mirror, instead of signal, there is only noise on pitch and yaw. So I opened the box of PSD, found out there is no red laser beam coming out from the chamber, so checked the laser box and moved a bit the mirror to align back the beam.
Then I tried to change the matrix. The situation is when we send noise in yaw, we have high coherence in pitch. But actually the matrix we use for this situation, the coefficient of two coils for pitch is zero. So it seems a bit strange to have this situation. Then I tried to change the coefficient for the three still-working coils little by little, the coherence of pitch got smaller, but still there.