Hi David,
We just went through the procedure to get our ILM He probe meter calibrated by Oxford Instrument.
Our model is different than yours, but, at the risk of stating the obvious, have you considered re-calibrating your probe? (one point at 100% just after a fill, and one point at 0% just before a fill, by pulling the probe just above the level of the liquid He -> this is a tricky procedure that can only be done by experienced service personnel).
The meter should give you an Err message if the probe is unplugged.
Switching the meter off then back on may also resolve the issue (make sure all your settings and calibrations are stored into the meter before you do that).
In any case, make sure you have a full He tank before troubleshooting the meter, as you will likely generate spikes of heat in the He tank during the troubleshooting process.
Good luck
Best Regards,
Hélène
Dr. Hélène Citeau
Scientific Instruments Specialist
Department of Chemistry and Biochemistry
Donald P. Shiley Center for Science and Technology
University of San Diego
5998 Alcalà Park
San Diego, CA 92110
Ph.619 260 2920
Fx 619 260 2211
On 3/2/12 10:35 AM, "David A. Horita" <dhorita_at_wakehealth.edu> wrote:
Hi,
With our (very) old Oxford 300, we have an HLM2 helium level meter that insists the magnet is at 94% (even if unplugged from the probe). Does anyone have a pinout/test method/manual for the meter (I feel better testing the meter than directly checking resistance on the helium probe itself).
It should read 100% at 0 resistance, so having it unplugged from the helium probe and reading 94% would suggest a problem with the meter itself, but I’d like to be able to check/diagnose.
Thanks,
David
-----------------------------
David A. Horita, Ph.D.
Associate Professor
Department of Biochemistry
Wake Forest University School of Medicine
Winston-Salem, NC 27157-1016
Tel: 336 713-4194
Fax: 336 716-7671
email: dhorita_at_wakehealth.edu <mailto:dhorita_at_wakehealth.edu>
web: http://www.wakehealth.edu/Faculty/Horita-David.htm <http://www.wakehealth.edu/Faculty/Horita-David.htm>
Received on Tue Mar 06 2012 - 08:23:29 MST