Hot Processor P4

[PsychoTech83]

Got a bit of a problem,

I've got a P4 machine here and the processor is running incredibly hot within seconds of being switched on. The fan is working as is the power supply fan.
No other components are running hot just the Pentium 4 chip.

I don't wan't to switch the machine on again as I don't wan't to do more damage.

It powers on but does not even get as far as BIOS before switching itself off.

Should I replace the mainboard or do you think the processor or something else is at fault?

many thanks

Martin

[Ric_]

Do you know that it is due to the temperature of the CPU?

It could be a faulty sensor for temperature, fan spinnage, etc.

[PsychoTech83]

Do you know that it is due to the temperature of the CPU?

It could be a faulty sensor for temperature, fan spinnage, etc.

yes, I've got a burn mark on the end of my finger to prove it

[Geoff]

Dust in the heatsink/fans?
Poor seal between the heatsink and the cpu?

[PsychoTech83]

just cleaned the dust off the heatsink and fans (not too much on there) .......it seems to have done the trick, I didn't realise how much trouble a small ammount of dust could cause.

I've left the machine running with the case off for a while to see how it behaves, seems ok at the moment

[Geoff]

Yeah, dust can be terrible in some of the more modern heatsinks. If the fins get clogged up it destroys the efficency.

[PeterW]

P4 cpus have a thermal cut off so they should cut the system off before they fry themselves. Do you know if its a 478 or 775 cpu? The 775 style fans do have a tendancy to come loose possibly if they have had a knock and its very difficult to tell that they are not pushed on correctly apart from a slight wobble of the heat sink if you wiggle it.