Abstract:
PRFPMI was recovered after IFI vacuum evacuation.
PRMI seemed to be unstable at first and I manually engaged 10dB gain at PRCL loop manually to stably lock PRMI.
However, the unstability of PRMI seemed disappeared after locking PRFPMI once and the unstability was not observed from the second lock trial.
We need to investigate what happened.

Detail:
After opening the GVs around IFI, we started alignent for PRFPMI lock.
GRX, IRX, IRY, GRY, and OMC alignent could e done without problems but PRMI alignment was very unstable.
PRCL control seemed to be oscillating at low frequency, I increased gain manually, lock PRMI, and aligned it.

After alignment was finished, I tried to lock PRFPMI but failed several times due to the unstability of PRMI.
So, I set 10 dB gain  in PRCL control and then handover was succeeded.
After that, PRFPMI with DC readout could be locked without the other problems (Since PRCL loop started to oscillating after handover from 3F signals to 1F signals, I disengaged 10dB gain).

I first thought somehow PRCL loop gain was reduced though I had no idea of the reason.
However, PRCL unstability was disppeared from the second lock trial and PRFPMI can be locked without any problem now though I didn't change the setting...

Since I haven't checked PRMI 3F lock loop, it might be better to check their performance.