Thank you so much Mike!
Yes, we contacted Bruker through the official channel. The issues appeared
after the coldhead replacement. Bruker engineers have resolved the problems
except the PreampHeat and PreampDev fluctuations. We are still unsure what
triggered these issues. While it seems that no apparent impact to the
smaple measurements based on the conducted tests.
Best regards,
Banghao
________________________________
> From: main_at_ammrl.groups.io on behalf of Michael Groves via groups.io
> Sent: Thursday, December 11, 2025 6:05 PM
> To: main <main_at_ammrl.groups.io>
> Subject: Re: [AMMRL] CPI- cryoprobe had a fluctuating PreampHeat and PreampDev values
Hi Banghao,
-71 is pretty dang low. I'm not sure if the diodes in the preamp will even
operate at that temperature... I'm not sure if you've contacted Bruker through
the official channels but... There is an adjustment for this. I don't think
we normally recommend customers do this on their own. The best solution is
likely going to be to call the service department and get somebody back to
take care of the issue that they caused. If you haven't, I would recommend
you get in touch with rover_at_bruker.com or someone similar and send in some
logfiles so that they can have a look and make sure nothing is too haywire
before they recommend any adjustments.
Cheers,
Mike
On Thursday, December 11, 2025 at 10:35:24 AM EST, Banghao Chen via groups.io wrote:
Dear all,
Our 700 MHz AVIII spectrometer with a CPI- cryoprobe recently had a fluctuating
Preamp Heat and Preamp Dev values :
After CP10-k replaced the cold head, the preamp temperature now reads ~71 K,
which is much lower than the 77 K setpoint.
Particularly, both Preamp Heat and Preamp Dev values are unstable and keep
fluctuating. We have tried many ways but could not resolve the issue.
Has anyone encountered a similar situation before? Your tips are appreciated.
Best regards,
BHC
******************************
Banghao Chen
NMR Facility Director
Distinguished University Scholar
Florida State University
Department of Chemistry and Biochemistry
102 Varsity Way, Tallahassee, FL 32306
chen_at_chem.fsu.edu
o: (850) 644-3334
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Received on Fri Dec 12 2025 - 15:39:16 MST