After purchasing a lot of 3 old Macs at a yard sale we discovered that the Mac Classic II would not boot. Googling for an answer always seemed to return the same results - the usual culprit is leaky capacitors. Capacitor fluid is semi-conductive and if residue leaks onto the board, electricity can flow between components it shouldn't be flowing between. What's the solution to this? Believe it or not, WASHING THE LOGIC BOARD IN THE DISHWASHER!! I was skeptical, but lo and behold, it worked! Have a look.