Re: [AMMRL] VNMRS tuning problems

From: Spin-Doc <bert.heise_at_spin-doc.net>
Date: Tue, 23 Apr 2024 22:51:17 +0200
Hi,

Please check the three +/- 18 & +7 V voltages on the bottom connector of the board inside the RF Front End (also, is a green LED lit on it?) - possibly one of the XP Power supplies has given up. Often they can be repaired by replacing the (typically dried up & leaking) large 400V capacitor, or buy a replacement supply from e.g. Farnell.

Cheers
Bert

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Am 23.04.2024 um 22:45 schrieb Casey Simons <csimons_at_uoregon.edu>:

Greetings all,

I recently got a probe back from repair.  Reinstalled it, went to tune it (ssNMR, manual tuning) and only got noise on all channels.  I checked the probe with a network analyzer, it tunes; test the system out by attaching a different probe.. Still noise.  I have 5 mV AC at the cable and have a standing wave signal (thank you fancy oscilloscope).  I can even get spectra when tuning before hand then reattaching the console to the probe and pulsing.  

I was wondering if anyone else has seen anything like this and can direct me to what may be causing my problems.

C

Casey Simons
NMR Director
CAMCOR Nanofabrication and Imaging Facility
University of Oregon
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Received on Tue Apr 23 2024 - 13:51:33 MST

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