We are seeing an oddity with the lock on a Gen III broadband probe
installed on an Inova system. After pulling the yellow stick on the
probe down, we were able to turn on the lock circuit of the probe.
However, while I can get an apparently stable lock profile display,
the digital lock level shown in the acqstat window fluctuates from
95% to 35% every five seconds or so. Oddly I don't seem much change
at all on the remote status unit's lock meter. The fluctuations seem
to be independent of both the lock power and the changes to the
air supply (so it isn't due to wobble in the spinner position).
We have never seen this behavior with any other probe or system.
Does this phenomena sound familar to anyone? This is with a 10 mm
tube of 100% D2O.
Jack
ps We also are unable to use this probe on our Oxford VT controller.
I have had two explanations for this. One is that there is a
safety circuit required for the Oxford VT controller that the
old Gen III probes lack. The other explanation is that the
heater tends to go out on these probes. The behavior we see is
that the probe can only slowly change temperature (say from 15C
to 20C) and will stall out at around 18C and reset the Oxford
VT unit with a HW Error message appearing in the Acqstat window.
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Jack W. Howarth, Ph.D. 231 Albert Sabin Way
NMR Facility Director Cincinnati, Ohio 45267-0524
Dept. of Molecular Genetics phone: (513) 558-4420
Univ. of Cincinnati College of Medicine fax: (513) 558-8474
Received on Thu Nov 09 2006 - 09:50:38 MST