Report for 18th of December 2020.

With Hirata-san and Yano-san.

Pictures at SR3 remedying work after O3.

After receiving and cleaning new screws we were able to replace the F0 keystone assembly top plate by a lighter one:

• Old plate + screws = 1096 g.
• New plate + screws + 5 new ballast plates = 1000 g.
• Old plate = 1053 g.
• New plate = 359 g.
• New ballast plate = 120 g

The new assembly is 96 grams lighther in order to compensate for the additional mass of the new F0 yaw stepper motor with limit swtiches. The aim was to remove 98 grams per klog 15541.

We left the IP and F0 locked. We aim to release them next week.