Dear Colleagues,
Thanks for your many suggestions concerning my wandering homogeneity.
I managed to come to many erroneous conclusions in the course of my
investigation. I am presently convinced that one of Phil Louthan's
original suggestions was the correct one - that the anti-vibration
table was moving because of variations in compressed air supply.
I did put the table down to test this, but the floor vibrations
disrupted the spectra so much, I mistakenly thought the homogeneity
was still wandering. Now, I have seen lock fall away and correlated
it with a pressure drop and I'm convinced that my compressed air
dryer is plugged and giving me insufficient pressure to hold the
anti-vibe table steady.
But, to thank you, I should like to apprise you of something that no
one recommended to me and that I discovered only by accident: the
Super Shim Diagnostic Program as described in the Inova Technical
Reference, pub. no. 01-999047-00, Rev D0801. The instructions
indicate that you need a special communications program like Procomm
Plus, but there is a utility built into Windows called Hyperterminal
that works just fine.
Serial and parallel ports are not present on some new computers.
Luckily, our Dell laptop had the serial port (DB9 male). The serial
port on the shim supply, however, is a female DB9, so we had to use a
gender changer to use our female to female cable.
I captured the output from this on-board program and you can view it
at my web site below - go to Facility Maintenance Procedures. Of
course, I welcome your comments about any of the content on my web pages.
While we were investigating this problem, we discovered a lot of dirt
and a noisy fan in the acquisition computer, so we are doing a
thorough console cleaning right now.
Bill
William C. Stevens, Ph.D. Director
Nuclear Magnetic Resonance Facility
Southern Illinois University
Carbondale, IL 62901-4405
618-453-6498 voice -6408 fax 521-9892 cell
http://opie.nmr.siu.edu
Received on Wed Jul 12 2006 - 13:22:00 MST