I've got a 600 MHz DD2 system that is struggling with autolocking. It will autolock onto acetone reasonably well and will not for chloroform. I can get the system to manually lock but in both cases the lock signal is extremely unstable. I've also seen an odd sinc function on the left side of my lineshape peak. This only occurs inconsistently on the very first acquisition after locking and shimming. The second experiment appears normal. All gradient profile appear normal if noisy.
Things we have tried:
1 - shimming - seemed to help for awhile, problem started again within 24 hours
2 - rebooting the console - seemed to help for awhile, problem started again within 3 days
3 - checked outputs for the lock XCVR - lock transmitter output was 3.8 V pp
signal at probe - 1.74V, pw lock scan on 5.12 ms, pw lock scan off 51.2 us
These seem to be the correct values to me, am I correct?
4 - ran 'Lock Gmap/Z0' calibration experiment - seemed to help but stopped locking again within 20 hours.
Does anyone have any ideas what we should try next?
Thanks!
Victoria
Received on Fri Feb 23 2018 - 10:50:47 MST