the waves are gone on the sample edit screen, please help.

I recently moved and expanded the memory on my mpc2000xl. now that I'm hooked up again, I don't have any waves on the sample edit screen, its just black and blank. the sounds are their, and I can do it using my ears, but its a major headache and I'm stumped...any suggestions? thanks

Its possible that you sampled the sample on a low volume....