(These instructions assume you are familiar with basic Macintosh procedures, if you are not, see a Macintosh manual or the tutorial which is on most Macintosh computers. Throughout the following, MB means mouse button.)
Obtain a 1d proton spectrum and zoom on the peak that you wish to decouple (for instructions see Acquisition and Processing of 1D H-1 Spectra). Put the cursor in the center of the peak that you wish to decouple, hold down the shift key, and click the MB. A cursor will appear and the decoupler frequency will be set to the cursor position.
Move the cursor to the Console Button and click the MB. Move the cursor to the FREQ Button in the upper left corner of the Console window and click the MB. Go to the DECOUPLER (F2) area of the Console window and make sure the Decoupler Gain is set to 60 dB. Go to the DECOUPLER (F3) area of the Console window and then to the two parameters under Homonuclear Control. The PW should be set to 50 us and the PD should be set to 40 us.
Move the cursor to the Decoupler Mode box and hold down the MB. If HOMO gated does not appear in the pop-up menu, drag to HETERO decoupling and then drag right to HOMO gated. Go to the Decoupler Mode box again, hold the MB down and drag to Decoupler OFF and then drag right to Decoupler ON (DN). Collect your spectrum and then turn the decoupler off by returning to the Console FREQ window. Put the cursor in the DECOUPLER (F2) Decoupler Mode box. Hold the MB down and drag up to Decoupler ON and then right to Decoupler OFF (DF).