When this happened here it turned out the turbo was at fault.
You can check the turbo status LED's with it still in place. Ours face
down so needed a mirror (or a very small head.)
On 3/24/2015 3:39 PM, Theiling, Bethany P (382D-Caltech) wrote:
> Hi all,
> At least one of the two Pfeiffer Duo 2.5 pumps on the dual inlet of
> our MAT 253 will shut off after ~15 minutes. The pressure will decrease
> fairly rapidly, then increase, and stabilize for ~5 minutes before the
> pumps shut down. I’ve checked both pumps using a vacuum gauge: both
> almost immediately read 7 millitorr when turned on. Both pumps
> immediately turn back on after shutting down the “inlet pumps” on the
> front panel of the IRMS, then turning back on (suggesting they aren’t
> necessarily overheating). We cleaned the Pirani gauge earlier today (as
> NO pressure change was being recorded earlier), which solved one
> problem. Any suggestions for troubleshooting and repair are welcome.
> Bethany P. Theiling, Ph.D.
> Caltech Postdoctoral Scholar
> Jet Propulsion Laboratory
> 4800 Oak Grove Drive.
> Pasadena, CA 91109
Department of Geological Sciences
1272 University of Oregon
Eugene, OR 97403-1272