Dear AMMRL,
we are having a problem with "missing frequencies" on the X-channel
of our VNMRS-600.
This shows up in a couple ways. First, we are seeing a large number
of U-shaped dips in the tune display that obscure our ability to
tune the probe for certain nuclei, for example Sn-119.
I have posted a screen capture of the problem:
http://www.nmr.ucdavis.edu/ammrl/mTuneScreen.pdf
We have tried the obvious things like switching probes and replacing
the cable to the probe. The problem is present with different probes.
The problem only occurs on the X-channel; proton is fine.
Second, if we use an external scope we can tune the probe fine to the
nuclei "obscured" in mtune, for example Sn119. However when we try
to acquire an Sn119 spectrum we see nothing, even for a concentrated
standard sample we normally see on one scan. So the problem is more
than just the tune display, certain frequency regions are now "gone"
and not observable.
Any ideas on solving this would be greatly appreciated.
Jeff
Jeffrey S. de Ropp, Ph.D.
NMR Facility
UC Davis
One Shields Avenue
Davis CA 95616
jsderopp_at_ucdavis.edu
530-752-7677 office
530-752-6480 MS1-D Lab
530-752-5682 600 MHz Lab
530-754-8238 Chem NMR Lab
530-752-3516 Fax
NMR Facility Web site URL is:
http://www.nmr.ucdavis.edu/
Received on Tue Apr 22 2008 - 09:40:17 MST