After installing 3 new T240 last week on ISI-BSC6, we faced off a centering issue on one of them after bolting the seismometer to stage 1. This morning, we unbolted the malfunctioning T240 and gently moved it. We put it back in place without attaching it to stage 1. This time, the centering process worked successfully. We measured powerspectra in the X-Y-Z directions. These spectra are in good agreements with the reference powerspectra.
We bolted the POD to stage 1 and re-measured powerspectra. The spectra still look good. However, this seismometer will be replaced as a precaution in the coming days.