Hello Everyone;
Does anyone have any advice or tricks they are willing to share concerning
procedures for balancing a receiver for an Inova spectrometer? We recently
got a new (refurbished) receiver, but the images or ghost peaks are > 2%.
(For comparison, on one of our old receivers they are ~0.2%.) To minimize
these a tiny potentiometer--R32--in a shielded compartment on the board has
to be adjusted. This involves killing exproc; turning off the digital and
RF card cages; removing the cabling; removing the board; removing the
shield; and guessing which way and how much to turn the screw (I presume
small changes); the process is then reversed, with the addition of waiting
for the lock to stabilize before taking a spectrum. Is there a better way
(without spending the thousands for an extender board)? Further, is it
relevant that when I do this on the Inova 600 and phase the true peak
(residual water in D2O) so that it is absorptive and positive, the image
peak is dispersive, at times down-up, other times up-down? (When I had
tried this on the Inova 500 the ghost peak was also absorptive, but
sometimes 180 degrees out of phase with the true peak.)
Any help will be gratefully acknowledged!
Thanks,
Karl Koshlap
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Karl M. Koshlap, Ph.D.
Manager, Biomolecular NMR Laboratory
Department of Biochemistry & Biophysics
Texas A&M University
College Station, TX 77843-2128
Tel: (979) 458-2272
Fax: (979) 845-9274
email: koshlap_at_tamu.edu
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Received on Mon Mar 29 2004 - 08:06:37 MST