Hi Ken and AMMRL,
We recently observed oscillations in the WOBB curve of all channels on a solids
AV II instrument, which we ultimately traced back to a failed LT1083CP regulator
on the 12V rail of the PSM3. The rail was outputting ~20V instead of 12V.
Frustratingly, the PSM3 LEDs were all lit even though the regulator was faulty.
Replacing the regulator fixed the problem.
However, since your issue is only on the 13C channel, I suspect our similar
symptoms have different causes. This may be a long shot, but if the calibrated
13C pulse width is longer, perhaps there’s an issue in the HPPR slice?
Best,
Sameer
--
Sameer Al-Abdul-Wahid, Ph.D. | Manager
Nuclear Magnetic Resonance Centre | University of Guelph
519-824-4120 Ext. 58914 | s.wahid_at_uoguelph.ca
http://nmr.uoguelph.ca/
> From: main_at_ammrl.groups.io on behalf of Kenneth Sharp-Knott
> Date: Wednesday, May 29, 2024 at 12:20
> To: main_at_ammrl.groups.io <main_at_ammrl.groups.io>
> Subject: Re: [AMMRL] Frequency ocillation in wobb curve on Prodigy TCI probe
Sorry, forgot the image...
[cid:826367ff-a837-4feb-ab0d-13d9b516e8fb]
Ken Sharp-Knott
Manager of Analytical Services and the NMR Facility
Department of Chemistry
Virginia Tech
(540)267-6502 (Cell)
(540)231-0885 (Office)
________________________________
> From: main_at_ammrl.groups.io on behalf of Kenneth Sharp-Knott via groups.io
> Sent: Wednesday, May 29, 2024 3:19 PM
> To: ammrl_at_groups.io <ammrl_at_groups.io>
> Subject: [AMMRL] Frequency ocillation in wobb curve on Prodigy TCI probe
I'm experiencing what looks like a frequency oscillation through the C13 wobb
dip. I don't see evidence of it in 1H or 2H wobb curves.
I was it was worse yesterday to the point that 13C sensitivity was significantly
reduced, which is what brought it to my attention. After a console reboot, computer
restart, cf, etc... Sensitivity seems to be about normal, but I'm still seeing this
oscillation.
Has anyone seen anything like this?
Ken Sharp-Knott
Manager of Analytical Services and the NMR Facility
Department of Chemistry
Virginia Tech
(540)267-6502 (Cell)
(540)231-0885 (Office)
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