Theres this non branded comp; it starts when powered on but only 4 10 to 15 sec n then goes off leaving the power led on. Any attempts to boot it again after that are futile until i unplug the power cable n wait 4 5 to 10 sec,until the power led on the comp is off, then it can power on but still with the same problem recuring. I have tested it n found that the mobo n processor are just fine. The mobo has two power inputs from the psu. When i unplug the smaller power input, leaving the biger one pluged in, the comp works just fine but without the peripheral components. But when i plug in the small power input, the shutdown problem resumes. Can anyone please assist me? Thanks

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Hmm this could be your power Supply or Your Heatsink not attached properly to the motherboard.

Try to lift your your Heat sink to see if it's loose or not mounted properly, be careful though it's not meant to take abuse.

Yea, the heat sink is not firmly fastened onto the mobo. I tried to hold it tight onto the mobo but the same problem recurs. Please explain to me how my problem could be heat sink or psu. Thanks

what processor/mobo do you have? is the fan spinning?

You should unmount and remount correctly.

. Please explain to me how my problem could be heat sink or psu. Thanks

processor will over heat ans auto shutdown if heatsinc is not install correctly ,and snug and tight by the fan heatsinc clamps not you hand .

psu can over heat as well, as inside it has many the same components as a computer motherboard and if capasitors are bad it will heat up and turn off as well !

Please explain to me how my problem could be heat sink or psu. Thanks

Sorry didn't read your that part correctly. but Caperjack is right. It is a self defence mechanism, so as to not melt the CPU on the socket (actually I am not sure if that can happen, theoretically it should be possible)

never made one melt but have intentionally mad a amd 1000 cpu smoke and never work again just by removing heatsinc and fan for about 10 seconds

lol, I should try on my 486, hmm or maybe I should ebay it, it may hold collector value.

the 486 may actually work for a bit before it overheats ,as they never ran as hot as AMD and bigger Intrll cpus

Hmm I dug the system out, it's missing Ram sooooo, yeah nvm. (I will never find the SDIM chips)