For the new generation of NMR users who are not familiar with manual shimming:

1. In Topspin, lock the sample
2. Type lockdisp to display the lock window.
3. type bsmsdisp to display the shim window.
4. In the bsmsdisp window, find the buttons z and z2
5. Click z. Click Step Size. Change it to 10
6. Click the + or – button to adjust z value and watch if the lock line is going higher or lower. Adjust z such that lock line goes higher. Do it until the lock line does not go any higher.
7. Click z2. Change step size to 10. Repeat step 6 for z2.
8. Click z and repeat step 6.
9. Repeat steps 6 – 8 until the lock level does not go any higher. you are done.
10. Sometimes after you adjust, the lock signal goes out of the top of the window. When this happens, find the Auto – Gain button and click once. This will automatically adjust the lock signal gain and bring the lock signal back in view.