The two things I am most interested in working on are: 1. I have a Mac SE Superdrive. It doesn't want to boot correctly and I get an image of a disk with a question mark when I turn it on. One time I used a Desktop Diagnostic disk and I was able to get into the computer. It suggested there was damage to the hard drive and asked me if I wanted to re-initialize (?) and I said no as I wanted to see what was on the computer. That was a mistake because since then the same diagnostic disk will not do anything. A "Macintosh Basic" introductory disk also works on it but I can never get to the desktop screen. It's been frustrating for sure. 2. Trying to get one of my Commodore 64's to work with sound. I don't know if the only way you can do it is to buy the correct chip (the 6581?). I've never replaced something like this... I think it doesn't need soldering but I'm not sure and I'm hesitant to buy the chip if that isn't the solution or there is a better work around. David K.