Press more than one key at a time?

[Droobie]

Hey fellas - I did a search before posting, but didn't find anything that worked.

I'm running some emulators on my Sprint Mogul, but i'm running into problems because I can't touch more than one key on the keypad without it cancelling the prior key. Makes it tough to have Mario run around the level...

I tried a fix from some dude on the forums for the 6700, but it doesn't have any effect on my 6800. Does anyone know of a cab or even a registry fix that will allow for more than one key to be pressed at a time on the 6800? Thanks in advance!