Robert,
I had a similar problem recently where random samples didn't descend
completely into the magnet and the SampleCase tried ejecting and
inserting several times until it finally gave up. Cleaning the upper
barrel with a "Q-tip" and isopropanol didn't solve the issue until I
made a different Q-tip designed to go lower where the shaft of the
spinner rests. I haven't had a single problem with any sample not
sitting fully in the magnet after that.
Eugenio
On 1/26/26 1:55 PM, Robert Peterson via groups.io wrote:
> Hi everybody,
>
> I have an annoying problem that's becoming more and more frequent:
> dummy samples getting stuck in our SampleCase sample changers.
>
> See the attached picture. We've always had users insert dummy samples
> into the magnet after they're done running their experiments (if no
> one is waiting to get on the instrument). The dummy samples that we've
> been using for the last several years are these solid black
> combination spinner/samples. I'm pretty sure we got them from Bruker,
> but I can't find them anywhere on the Bruker website so maybe they've
> been discontinued.
>
> We've always had a problem where are these dummies samples get stuck
> in the SampleCases. It's most often during the process of ejecting the
> sample - the dummy sample gets stuck in the mechanism as it tries to
> drop it back down onto the sample holder. When that happens, someone
> has to go up on a ladder and gently push it down so that it will drop.
> It occasionally get stuck above the magnet, which is harder to deal
> with. A separate problem is that it often has trouble inserting the
> dummy sample into the magnet - the sample descends into the magnet but
> never reaches the bottom and gets detected. Then the system ejects the
> sample (all the way back out onto the sample rack) and then tries to
> re-insert it. Sometimes it goes through this cycle three or four times
> before it finally goes in and the system detects it.
>
> These types of insert/eject problems almost never happen with ordinary
> samples.
>
> The main problem (where the dummy sample gets stuck in the mechanism
> as it tries to drop it back down onto the sample holder) used to
> happen a couple times a week, but recently it's been happening several
> times a day. Has anyone else experienced this? Is there some
> maintenance I can do on the SampleCase to prevent this kind of thing?
> Or is this type of dummy sample just problematic (possibly the reason
> that Bruker discontinued them)? What type of dummy sample do people
> recommend using? Or are dummy samples not really necessary on heavily
> used instruments?
>
> Thanks in advance, and I'll summarize any responses.
>
> -Robert
>
>
>
--
Eugenio Alvarado, Ph.D.
NMR Facility Director
Chemistry Department, room 3500. University of Michigan
930 N. University Ave., Ann Arbor, MI 48109-1055.
Voice: (734)-764-9924
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Received on Mon Jan 26 2026 - 11:52:24 MST