[AMMRL] CPI- cryoprobe had a fluctuating PreampHeat and Preamp Dev values

From: Banghao Chen via groups.io <chen=chem.fsu.edu_at_groups.io>
Date: Wed, 10 Dec 2025 16:25:33 +0000

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<mailto:chen_at_chem.fsu.edu>
o: (850) 644-3334



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Received on Thu Dec 11 2025 - 07:35:24 MST

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