I read this in the drive upgrade...

If you will be adding a second disk drive to the Mark 1, you will need to purchase a proper IDE connector cable. Not just any cable will do, it must be the proper length. There's very little room inside the case, and if you get a cable that's too long, you'll damage the components trying to cram the cable in there. The correct cable can be purchased from Videk, part #3017.