Two suggestions: 1) In the "Service" tab of the Topshim panel, there's a "calibrate" feature that you can use to get the system talking to the probe more effectively. Last year, we sent a probe out for service and when it came back we had a terrible time shimming it with Topshim. Once an engineer who happened to be onsite pointed out this button, we clicked it and let the software do its thing and we were then able to Topshim very effectively.

2) If you're primarily running organic samples, I've found we get better 3D shims by using an ASTM standard (40% dioxane in benzene-d6) and using the command "topshim astm 3D". We do this as part of our weekly maintenance with a doped ASTM standard, which also affords us easy access to quickly calibrating carbon 90-degree pw's.

Dear Ferron,

please provide the topspin version, you can start trying with "topshim gui" select 3d shim and use 10% d2o and 90% h2o sample, after finishing save this shim.

now put line shape and then try the "topshim" only. if you see the improvement then do a little bit manual shimming of z, z2, z3. depends your spectra -how it's shape showing.

Other wise try with - lineshape and take hump optimization in "topshim gui" command.

It should work very fine..otherwise need some checks- Hardware; 2H pulse length; 2H amplifier; Gradient; Probe coil cleaning; Probe insert cleaning.

hope this will help you.

Man Mohan

1. try with standard sample (1% CHCl3 in Acetone)
2. check sample position in spinner and solvent height - are them ok? Maybe, in contrary, too much solvent and experiment is on elevated temperature?
3. Try extra parameter convcomp (convection compensation). Works under stable VT conditions (also check.
4. The last, but not least: sample homogeniety. Solid particles, high viscosity, aggregation?