View Full Version : Macintosh Classic with power supply issues

May 28th, 2010, 05:22 AM

A while ago I got hold of a nice little Macintosh Classic. It works, but the internal HDD does not spin up when connected to the internal PSU (It spins but stops), and the monitor has a shaky picture, and with every mouse click the screen contracts a little. Same for floppy reads (even more) and sound output.

I connected a scope to the +12v and +5v lines on the HDD power supply cable, and sure enough, the voltage fluctates quite a lot, and you can see it sag in unison with the monitor wavyness and the floppy reads etc..

Question is, where to look first? Any specific caps I should replace?