At about 12:30 LT the main turbomolecular pump of PR tower went in failure and was then valved off and stopped. During this phase, we also accessed the 'plarform' for visual inspection , and large mechanical/seismic noise was produced. The 'back-up' turbomolecular pump was then activated, and the operating conditions were restored at about 13:50LT.

We plan to replace the main turbo pump during the maintenance break to ensure that both pumps are operational for standard system functionality.