There are a few different ways to clear the memory on the Model 4000. The most common method is to access the 4000 through the front panel.
Hit F1 to enter the 4000s access code.
Enter you password and hit enter.
Hit F6 to get more options.
Hit F2 to reset the 4000. The 4000 will warn you that your are going to erase all your programs if you wish to continue hit enter. If you want to cancel out of this screen you can hit the menu recall button.
Your Model 4000 will now be back to the factory defaults.