1) Opened the PR3 chamber.
2) Checked the height of keystone in the SF. It was 64.5mm.
3) Checked the FR of SF. The slider was in the lower side, but it can still move.
4) Adjusted the height of keystone by the FR to be 65.5mm.
5) Made the upper stopper for keystone be higher by 1~2mm.
6) Closed the chamber (not yet fastened by bolts).
