Hi, All:
Many thanks to all who responded to my plea. As it happens those who
indicated that it was a shim that was over voltage were right on the
money. Thanks to Clemens Anklin, the "fix" was quite easy. Since our TXI
was functioning normally, we simply loaded the shim file from the TXI (it
was immediately obvious that the glitch was gone) adjusted Z, Z2, X and Y
so that the lock was at a reasonable level, then did Topshim 3d. We're
close to back to normal; perhaps some of the higher order shims may need to
be adusted. As it happens, there were several higher order shims that
seemed a bit excessive--over +/-40,000.
While this may be old hat for many of you, I share this for those of you
who are, like us, relative novices with respect to fixing NMR spectrometers.
Thanks again to all.
Robin
--
Robin B. Kinnel
Silas D. Childs Professor, Emeritus
Department of Chemistry
Hamilton College
198 College Hill Road
Clinton, NY 13323
315-859-4725
FAX 315-859-4807
Received on Tue Dec 02 2014 - 06:51:11 MST