Mac not powering up.
I've been doing phone repairs for a few years, and a friend has an iMac A1224 which won't turn on. So said I'll have a look, I've never done one, so thought it'll be a good one to learn.
So basically, power it up, screen stays black, but it makes the startup noise (or beginning of it) and just loops on this noise?
Any of you pros know what causes this?