Hi, I purchased a used E2PROM catridge thinking it would be great with my SD-1. The board however doesn't acknowledge the cartridge. So I wonder whether the failure is in the EPROM or on the keyboard's interface? Or did Ensoniq makke more than one type of cartridge? It doesn't list any particular model for which it might be intended, or what is its capacity. Maybe someone else has been in this spot and could help me out. Thanks!mn