this is all new to me. Am not a MAME person yet. Please explain how to make this work. I installed the area 51 chd file on the CF card put it in the adapter and put it in the game in place of the original HD. I get music but no picture and then after a little bit I get garbled screen crap and just tones for sound. In what format does the file have to be in for the original boardset to use it?