Just when you think you’ve seen everything, some jobs catch you by surprise. This particular desktop PC had been checked out by my colleague who correctly diagnosed the symptoms (powering down after a minute or two) as an overheat. He dusted the case with air and re-pasted the CPU. The computer then seemed fine and it was handed back to the customer straight away, a typical ‘while-you-wait’ issue.
However the customer was back later that afternoon reporting the same issue. I took the side panel off and powered up the machine. I then set about inspecting the fans to make sure they were spinning up to the correct speeds. It was then that I noticed the graphics card fan blades were completely missing, only the commutator remained. I then found this fan in the bottom of the PC case, cracked beyond use. I replaced the graphics card with one of a similar specification and the problem was solved.