We found a leak in the vacuum ducts of Xarm at the pump port of X-15 and also found that the pumping unit at X-27 stopped.
The leak is at an angle valve to introduce dry air in to he ducts.

As a result, vacuum pressure of the Xarm was increased. Values in () were obtained 2018/1/31.
*X-2 [260m]1.3*10^-4 Pa (3.3*10^-6 Pa)
*X-10 [1060m]1.9*10^-3 Pa (1.9*10^-6 Pa)
*X-15 [1580m]1.5*10^-2 Pa (2.6*10^-6 Pa)
*X-21 [2180m]1.5*10^-3 Pa (1.1*10^-5 Pa)
*X-27 [2780m]2.5*10^-3 Pa (2.0*10^-4Pa)

Thanks to T. Tomaru and N. Kimura, the leak point was temporally repaired and the pumping unit was restarted.