Hi! Maybe not really classic computers, but one need a good oscillioscope to fix problems in old computers... My HP54615B has a dead powersupply. It just ticks once a second or so. The fan just rotates slowly. Does anyone has an idea what component has failed? I have checked som transistores and diodes, they all seem to be fine. I am about to replace som capacitors now. Maybe there are someone out there that has the schematic for this scope??? /Mattis Lind