Don't know if this helps anyone but this happed to my PS3 super slim so I bought a new one, but I was curious to see if I could repair the old one. Firstly I took the HDD out the the one with the problem and installed it on the new one. HDD worked fine even though the second system insisted on formatting it. I ordered thermal paste, another PSU and a can of compressed air. I took the whole thing apart, blew all the dust out with the compressed air and cleaned off the old thermal paste with 99% alcohol , applied new thermal paste, swapped the PSU and put it all back together. Result; Exactly the same problem. So this to me says a couple of things, unless I got a replacement PSU with exactly the same problem, the fault is probably on the motherboard and is NOT shutting down due to over heating either. Probably some component has failed or heat-separated from the board. If you also search the web you will find lots of people asking the same question but no concrete answer, so again this leads me to believe...