There’s one topic we’ve been recently keeping track of under Using your Intel-based iMac at Apple Discussions. As of today, this 2-day-old post has been read more than 1,350 times. (See Screenshot 01.) One Mac user initiated a topic by saying that his or her refurbished iMac starts up with no problem but that it frequently restarts and shutdown itself. So far, this post has returned 32 replies. A dozen people or less share the same restart/shutdown problem. And a couple of Apple Authorized Service Providers (AASPs) or equivalent have jumped in.

The original topic goes

I recently bought a refurbished iMac from Best Buy. When I inspected the unit after I unpackaged it, nothing appeared wrong externally. Also, the setup and installation of the OS went smoothly. However, after turning it on and browsing the web on Safari, the iMac suddenly shuts down. I thought that the power cord might’ve had a short in it at first, but have since moved away from that conclusion. Now, whenever I turn on the computer it will boot up fine and then suddenly shutdown or restart.
And as I write this, there is a new symptom: as soon as the iMac loads the desktop, the fans start up really loudly and then the computer shuts down.

(See Screenshot 02.) One AASP technician says replacing the power cable will not fix the problem, which probably doesn’t surprise anyone. How about removing the cable that connects the logic board to the CD/DVD drive? One says disconnecting this cable fixed the restart/shutdown on his iMac.   Continue reading →