Dear folks: I found my turbo pump unit (TMH 262 and TMH 071) on the analyzer (MAT253) was off this morning. After restarting, the turbo unit won't be able to attain nominal rotation speed, which means that I won't be able to check source pressure on the mass spec. The back pump (DUO 5.0) are fine (pumping down to 10 ^ -5 torr). No leak on the line is detected. A call to Pfeiffer did not seem to indicate that the turbo pumps are broken. The turbo pumps have been pumping for 2.5 years, and I don't expect their life is that short. I know several scheduled and unscheduled power outages during the holidays were partially to blame, but any suggestion how to fix the problem will be appreciated. Best, Huiming -- Huiming Bao, Assistant Professor Department of Geology & Geophysics, E235 Howe-Russell Geoscience Complex Louisiana State University Baton Rouge, LA 70803, USA Tel: 225-578-3419 (office), -3413 (lab) Fax: 225-578-2302 http://www.geol.lsu.edu/bao/