In October, I was lucky enough to be asked to "dispose" of a PowerMac G4 Cube. It was complete but very dirty having being left in an outdoor shed for 11 years! I brought it home and gave it a clean, connected it, crossed my fingers and plugged it in. The fuse immediately blew in the plug and from researching the problem, it looked like the psu had died. As I couldn't get into the PSU and was quoted a lot of money to fix it, I bought an LED power supply rated at 28V, 250W and tried that. This time the computer booted up and ran. It worked fine for a few days except that there was a CD stuck in the drive. The CD was read by the computer and iTunes ripped it without an issue but it would not eject.
After a few days of normal use, I plugged in the PSU and heard a sparky sound and there was an "electrical" smell. Since then, the cube has been unresponsive. I checked the PSU with a multimeter and it is still producing 28.0V.
Could anyone offer any next steps in fault finding? I managed to use this machine to get hooked. It is very pretty and has pride of place on my desk. The keyboard and mouse were nice to use and it was usable on Mac OS 10.3.9. The last time it was started previously was 2007! I love macs and already have a 2005 PowerBook and a 2008 MacBook Air (both in regular use)