With Hirata-san, Ikeda-san and Horiuchi-san.

See pictures in album PR3 Remedying Work.

First we identified which cable was the one failing. The traverser uses four motors, they are labeled as R1, T1, R2 and T2. Given the orientation of the motors, very likely R stands for radian and T for tangential. Numbers 1 and two refer to the -Y and +Y side of the chamber respectively. Using the multimeter and a connector adapter we tested the electric continuity between pins that must be connected to the same coils in the motor. In R1, T1 and T2 cables there was continuity between pins 1 and 9, and between pins 2 and 3. However, in R2 there was only continuity between pins 2 and 3. It looked like the R2 cable was the one failing.

We opened the vacuum chamber, removed the cable and tested it with the multimeter. The cable was fine. Then connector attached to the motor was also fine. Then we tested the in-air adapter that connects to the flange. It wasn't working properly. See it has disconnected thread in this picture.

We put back the in-vacuum cable and used a different in-air adapter in the outside. There was continuity between pins 1 and 9 and between 2 and 3. The problem was the in-air adapter, not the in-vacuum cable.