AMMRL: loss of low-band power on a VNMRS

From: David Richardson <David.Richardson_at_ucf.edu>
Date: Wed, 18 Mar 2015 20:27:40 +0000

Hi All,
The C13 pw90 on my VNMRS went from ~10us at 56dB to longer than I cared to measure at 63dB. With a scope I found the input to the amp (tpwr=63 and no attenuators) was 12mV and the amp output was 2.5V. I switched frequency generators from the direct drive to a PTS500 and again got 12mV. I assume my issue is between the frequency source and amp and that 12mV going into the amp is too low. However, I am have reached the limit of my knowledge and am not sure where the signal goes between the source and the amp so I don't know how to troubleshoot from here. Any help would be appreciated.

Thanks,
David

P.S. Thanks to Robert Harker at UF for reminding me how to use a scope since it has been so many years since I had a need to do so.

David Richardson, Ph.D.
NMR Instrumentation Specialist
Chemistry Department
University of Central Florida
david.richardson_at_ucf.edu<mailto:david.richardson_at_ucf.edu>
407-823-2961
http://chemistry.cos.ucf.edu/nmr/
Received on Wed Mar 18 2015 - 10:27:46 MST

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