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Sorry, I had to write the Wizard of Oz answer.

Things to think about: the computer that you type into is the Master of the computer that is located on a board in the mass spectrometer itself. That computer board is the "slave". When the two are not in proper communication, problems arise. Its not just an annoying Windows moment, but a real control problem.

That may not have been clear to you. Master-slave. Its an old fashioned concept.

Marilyn

On Jun 19, 2008, at 11:02 AM, Troy Ocheltree wrote:
Hi All,

Thanks for your good humored response Marilyn - sadly enough I didn't see it coming.  But now I have to hang my head in shame a little bit as I didn't follow the second rule of faulty electronics.  Rule 1 - make sure its plugged in.  Rule 2 - reboot the computer.  So after a reboot and a quiet chant of 'there's no place like home' - it appears order has been restored in my lab. 

Thanks to all who replied,

Troy Ocheltree
Division of Biology
Kansas State University
116 Ackert Hall
Manhattan, KS 66506
tel: 785-532-3925



On Jun 18, 2008, at 10:14 PM, Andrew Schauer wrote:
We had a DeltaPlus Advantage shut down suddenly due to a dead turbo. Once all vacuum was restored, one cup was shorted to the secondary electron detector. I had to extract the detector array to remove the short...very very very tedious. I was able to take this photo as a result (http://depts.washington.edu/isolab/IsoLabimages/farradaycups.jpg). We found the short to be within the flight tube and thus the detector by following the circuit diagrams and checking for continuity and proper voltages. I hope it isn't this for you, but if the easy suggestions don't work, don't assume its this because it isn't trivial.

andy


Andrew Schauer
ISOLAB
Department of Earth and Space Sciences
University of Washington
Seattle, WA 98195

206.543.6327
[log in to unmask]


----- Original Message ----
From: Troy Ocheltree <[log in to unmask]>
To: [log in to unmask]
Sent: Wednesday, June 18, 2008 11:06:30 AM
Subject: [ISOGEOCHEM] faulty detector?

Hi all,

I'm seeing some strange symptoms on my Delta Plus after losing power during a recent tornado.    Unfortunately I was running samples when the tornado hit, so the source was on when the pumps stopped.  After pumping out the mass spec for a day I felt relieved to find my sensitivity to CO2 and N2 was still normal, and linearity and stability tests also looked good.  So I decided to run some samples, but after 17 samples I received a fatal error stating that the peak center failed.  When I checked the intensities for mass 28,29,30 of my N2 ref gas, the intensity of my center cup (mass 29) was low (0.28 V compared to 2.4 V).  I found the same low intensity on the center cup when I sampled my CO2 ref gas.  A mass scan on CO2 showed strange results for the center cup (mass 45).  The intensity of the center cup was fairly flat at around 0.2 V from BDAC values 2000 through 8000, but then at BDAC ~ 9000 the intensity of my center cup jumped to ~ 10 V and had a flat peak until BDAC 9300 then dropped back to 0.2 V.

Right after the tornado hit I was most worried about the source and my filament, but the symptoms don't seem to add up to those being the problem, plus box, trap, and filament currents are all normal.  Is this a faulty detector?  

thanks,


Troy Ocheltree
Division of Biology
Kansas State University
116 Ackert Hall
Manhattan, KS 66506
tel: 785-532-3925

Troy Ocheltree
Division of Biology
Kansas State University
116 Ackert Hall
Manhattan, KS 66506
tel: 785-532-3925








Dr. Marilyn L. Fogel

Geophysical Laboratory

Carnegie Institution of Washington

5251 Broad Branch Rd., NW

Washington, DC 20015

Phone (202) 478-8981

Main office (202) 478-8900

FAX (202) 478-8901

Website: http://fogel.gl.ciw.edu/