Central Instrument Facilities

The vnmr program does not respond to my commands, or it seems to "hang up".
1. There may be a console communication failure. See the instructions below for the "su acqproc" procedure.
2. If you are still unable to get a response from the instrument, please contact a member of the CIF Staff.
One or more of the windows has disappeared.
1. Look in the icon box at the bottom right and click on the icon for the window if you find it.
2. If the acquisition status window has disappeared, enter acqstat.
3. If the acqi button has disappeared, enter acqi to restore it.
4. If your are unable to restore your window, enter exit to close vnmr, then click on the spectrum icon at the bottom to restart vnmr.
After I login, or when try to join a new experiment (e.g., jexp2) I get a message that the experiment is locked.
1. Enter unlock(2) to unlock experiment 2. In the event this does not work, please contact a member of the CIF Staff.
The VNMR screen says it is locked by another user and I cannot login.
1. This may happen inadvertently. Contact a member of the CIF Staff.

Console Hardware

My sample will not eject.
1. If there is no air pressure, you will have to wait until the pressure comes back up. If it is critical that your sample be removed immediately, please contact a member of the CIF Staff.
2. There may be a console communication failure. If the instrument won’t respond, and the "acquisition status" window indicates "Interactive" or "Acquiring" try entering sa or aa to stop it. Occasionally, even that won’t work. In that case, open the terminal window. It should be in the icon box on the lower right. If it isn’t, right-click the mouse on the desktop, and select Programs and then Terminal. In the terminal window enter su acqproc once. The status should then change to "Inactive". Then su acqproc again, and the status should change to "Idle". This will cause the system to first kill, then restart exproc. After that the instrument should respond normally. If not, exit vnmr, logout, and login again.
3. If there is still a problem, you may need to reset the nmr console. Open the front door of the cabinet and press the reset button. Wait about two minutes for the reset procedure to complete, then try to eject again. You may need to repeat the "su acqproc" procedure. If it still won't eject, please contact a member of the CIF Staff.
I am having difficulty shimming.

Before opening the acqi window, enter rts(�shimfile�) to read the default shim values. Then enter load=�y� and su to load the shims. Then click acqi.

Magnet Hardware, Probe and Sample Problems

I am having difficulty obtaining a stable deuterium lock.

Your sample may be too concentrated.

The sample level in the tube may be too low.

Some solvents are more problematic than others, particularly when subjected to high lock power:

OK: D2O and CDCl3

Troublesome: Benzene, THF, andDichloromethane

Worst: Methanol and Aceton

My sample will not spin, or spins erratically

There may be dirt or contamination on the sample tube or spinner, or the tube may be warped. Remove it from the magnet and remove the tube from the spinner.

Gauge the tube in the glass gauge tube, and if it does not pass, transfer the sample and discard the bad tube.

Clean the tube and spinner with alcohol and a lint-free lab wipe, and replace into magnet.

There may be a fluctuation in the air pressure.

My spectrum has large baseline humps.

The spinner o-ring is either too loose or too tight.

There are decoupler problems.

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Variable Temperature Operation

What do I do if the temperature continues to rise above the set temperature?

If the temperature rises more than 5� C above the setpoint, the heater must be stopped before the probe is damaged. (The maximum safe temperature for the probe is 120� C.) The quickest way to stop the heater is to disconnect the VT cable from the probe.

Network Problems

I cannot ftp (or fetch) my files from the nmr workstation to my own computer.

Your password may have expired. Log into the nmr workstation, right-click the mouse on the desktop, and select Programs and then Terminal . In the terminal window enter passwd and follow the prompts.

I cannot print my spectrum.

On the menu bar click on Main Menu and Configure, then click Select Plotter until the correct printer is displayed in the message window. Do the same with the Select Printer button.

The computer is slow.

Heavy network traffic may slow down the system.

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