2009 Mac mini shutting down during boot, just after chime
My early-2009 Mac mini works normally *until* you have to restart it (which I have to do occasionally as it’s a dual-boot system).
When you restart it, about 7 times out of 10 it will shut down just a few seconds after the startup chime. It doesn’t show the “NO” symbol, or anything else - the startup chime sounds, the grey boot screen appears, and then it shuts down like someone’s pulled the power cable out.
If you keep trying, eventually it will boot normally and then everything will be fine - it will run happily for days, until I need to boot into a different OS and then the problem reoccurs.
It’s definitely NOT the hard drive (actually an SSD) - I’ve replaced it with a brand-new one with a fresh OS install, and the same thing is happening.
It’s also not the PRAM or SMC - I’ve reset both (and replaced the PRAM battery), with no effect.
Could it possibly be the fan? After 12 years of being on almost 24/7 (generally with just a few weeks off each year), I’m wondering if the fan bearing is starting to go bad, so isn’t always spinning up as well as it should and the machine is able to detect this and immediately shut down?