Cpu, North bridge and South bridge were found very hot. I think its normal but suddenly blackout. Thanks for your help vtech
This is just some information chucked in gratis, but a computer which suddenly blacks out, as you mention, is often due to one of the chips overheating, normally the CPU.
Generally speaking power dissipation is a problem with CPUs, bridges, graphics chips, and other high dissipation chips. This is especially the case for laptops.
There are three areas:
(1) The contact between the chips and any heatsink.
(1.1) The clamp holding the chip in contact with the heatsink loses tension
(1.2) The insulating medium between the chip and heatsink degrades and becomes a high thermal resistance. Heat sink compound goes dry and brittle (this is very common after around two years of high use). You can normally improve on the factory fitted insulating medium and sometimes clamping.
(2) The fan cooling system is faulty.
(2.1) Ducting clogged with debris
(2.2) Fan bearing stiff or seized
(2.3) Thermal sensor faulty
(3) Solder joints crystallized by heat (especially on laptops). This is increasingly a problem with the lead free type solder being used now.
The only solution here is to reflow the solder joints or fit a new motherboard.
The net result of fixing the above problems, especially (1) and (2) has been, in my experience, to convert a quirky computer with all sorts of odd random faults into a stable reliable machine.
In one case a laptop would work OK with all programs except Photoshop- that led me on a wild goose chase.
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