Hello Huiming, usually pfeiffer turbo pumps, controlled by a pfeiffer unit, have a standby mode which let them run @ 70% of their nominal speed. I don't know if the controller board of a 253 will permit such mode, may be. The other problem may be a leak issue in your MS, enough to prevent your turbo pump reaching the maximum speed but not enough to put your MS in save mode. joel A 08:59 11/01/2005 +0100, Deborah Rupprecht a écrit : >Hello Huiming, > if the pumps did not stop working because of some (un)sceduled power >outages, maybe a board or board unit was damaged ? > >Best regards and good luck, > Deborah > > >At 16:16 10.01.2005 -0600, you wrote: > >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/ > > > >***************************************** >* * >* Deborah Rupprecht * >* Institut für Pflanzenernährung * >* Rhein. Friedrich-Wilhelms-Universität * >* Karlrobert-Kreiten-Str. 13 * >* 53115 Bonn * >* * >* Tel. +49 -(0)228 -73 -3640 * >* * >***************************************** ************************************************************************* Joel Savarino Laboratoire de Glaciologie et Géophysique de l'Environnement/CNRS/UJF 54 rue Moliere, BP 96 38 402 St Martin d'Hères Cedex France tel: + 33 476 82 42 51 fax: + 33 476 82 42 01 Email: [log in to unmask] Web: http://www-lgge.obs.ujf-grenoble.fr **************************************************************************