[Richard Dave Jeff Brett Arnaud]
Today and yesterday we tried to understand why the beamsplitter suspension looks to be moving so much. In order to see higher frequency contents, we took a spectra with this time, test points channels (sampled at 16kHz). A large peak appears at 1900Hz for M1 top mass osem (2nd plot of the attached pdf) and M2 middle mass osem (3rd plot), as we saw few weeks ago on the TMSY after the power outage (see aLog 6338). The first and last plots are showing respectively the BS ISI motion (X and Y direction projected at the suspension point calibrated in um) and etmy suspension osem top mass signals, and none of them are showing such a feature.
To solve this, we tried fruitlessly several things
- power recycled IO chassis and front end h1susb123
- unplugged/replugged cables between satellite box/coil driver/AA chassis
to be continued [...]
Richard fixed the problem, cf his aLog 7246.
attached is a spectra (from same template as aLog above) after rebooting the coil driver