Have any other sites with Varian cold probes run into
the following problem? A few months back I noticed that the
2H tune insert wouldn't fully insert on our Varian 800 MHz
cold probe. Last week I noticed this had become worse and now
the 13C tune port position had problem with the insertion of the
tuning rod as well. We removed the heater assembly and discovered
that the holes for both of those tune positions are now partially
filled with extruded glue from the main heater assembly. The
glue that was used to fill that assembly appears have formed
crystals nearest those tune ports and expanded into their
openings. I was surprised to find that Varian would design
a heater assembly that had vertical holes intersecting with
horizontal ones such that any expanded glue could extrude
into the openings for the tune ports. I would be most interested
to know if any other sites have run into this and how Varian
resolved it for them. Since this problem has progressively
worsened, I am afraid to just try clearing out the tune ports
and suspect the heater assembly needs to be totally replaced.
Thanks in advance for any insights on this problem.
Jack
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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 Mon Jul 30 2007 - 11:42:45 MST