I would try cleaning the bore/transfer tube. My guess is there is some gunk
built up in there that is intermittently obstructing the sample from fully
inserting, but still getting far enough to trigger the sample down sensor
and be able to lock.
_____________________________________
Todd Rappe
Minnesota NMR Center <nmr.umn.edu>
612-625-9147 (office)
651-321-TODD (rings office and mobile)
612-624-8892 (magnet lab)
On Wed, Jul 15, 2026, 1:42 PM Smith, Scott K via groups.io wrote:
> This is a strange but consistent problem that seems related to Bruker
> spinners and just one of our automated spectrometers. Occationally a
> sample is inserted and immediately shows ~1000Hz linewidth on what would
> otherwise be a normal proton acquisition.
>
> The samples are properly sized and set in the spinners.
> The proton signal is strong, but lock is nearly gone.
> Ejecting and reinserting has no effect.
> The spinners themselves show no obvious defects.
> Change the spinner and shimming goes back to normal like magic.
>
> The problem was not reproducible on three other Bruker spectrometers with
> and without automation.
> A year ago this had become a near daily occurrence and we tried to isolate
> the "bad" spinners. Eventually there were more bad than good spinners so
> we ordered a new set for the sample case. For about six months the
> problem was gone. Now it is starting back up at a rate of a failure every
> one or two weeks. Now the "bad" spinners can be reused.
>
> The console is an Avance III HD with a Prodigy probe ca 2018 and a
> sampleCase. The magnet is a vintage unsheilded Oxford 500 ca 1982.
>
> Has anyone encountered what I have?
>
> keep 'em spinning
> Scott
>
>
> *Scott K. Smith*, Director of NMR Spectroscopy
> The University of Texas at Austin | Chemistry | 832-294-1928 |
> *utexas.edu* https://www.utexas.edu/
> NMRlab homepage: *IoNMR | Nuclear Magnetic Resonance Labs (utexas.edu)*
> https://ionmr.cm.utexas.edu/
>
>
>
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Received on Wed Jul 15 2026 - 12:13:28 MST