To clarify I am still on this AO1 Auto Orchestra made by MTI. As I couldn't even identify a resistor or such when I started I have read a lot and spent a lot of time on the internet and have solved a couple of the problems but am now facing close to 30 integrated circuit units. I know they can't be tested in the usual ways and I have even purchased a used analog oscilloscope(which I am learning how to use) and that they can be ruined by static electricity. What I would like to know is what to look for when testing these in the circuit. It will be sending signals that change chords, such as abcd etc., and a wide range of different drum and rythm sounds. Some of it now works but not all. I have a complete set of schematics and can trace all circuits on the six pc boards. But what I need to know is what kind of signal I see. Will it be voltage in different strengths that can be read on the scope? The unit uses a 120v transformer cut down to three 18 volt circuits using a center tap through a recitfier so all voltage is +dc except for one signal which is -2v. If I could tap into some of the brain power out there I may make this thing work yet. Will appreciate any help. Thank you. Also I check email about three times a day so if I don't answer right away I will soon. I am located on the west coast.