Bad PSU causing thermal event

[mwhidden]

Hello,

I have an Intel D865PERL Mobo with a P4 2.8GHz. I was having an issue with the computer powering off and coming back with the BIOS complaining about a thermal event. I ran the box for a while with Intel's active temperature monitor, but did not observe any overheating, even under heavy CPU load.

I checked the MB 4-pin power plug, and noticed some scorching, so I replaced the PSU in hopes that it was the problem.

Computer seems fine now, but I wonder why a bad PSU would cause (apparently) erroneous thermal events. What's the connection to temp and/or sensors?

 

[rolli59]

Bad electrical connection will heat up the circuit and can eventually cause fire!

 

[shovenose]

look for bulgind or leaking capacitors on the motherboard. these will cause that. so will a malfuntioning power supply.

 

[mwhidden]

look for bulgind or leaking capacitors on the motherboard. these will cause that. so will a malfuntioning power supply.

I know it is definitely the PSU, since the issue went away with the new PSU, as noted in the O.P. No bulging caps on the mobo, but I found one in the PSU. I was just curious why a bad PSU would cause a thermal event (vs some sort of "voltage" event or...?)

 

[mwhidden]

Bad electrical connection will heat up the circuit and can eventually cause fire!

I suppose that makes some sense, but the thermal event seemed to occur so suddenly. The temperature monitor software never saw the temps rise. Temps are normal, then instantly the box is powered off and when it comes back up, the BIOS says a thermal event occured. If the high temps are genuine, the spiked from normal to excessive in less time than it took the monitor to see them going up.

 

[shovenose]

it has to do with out-of-spec voltages or ripple of the psu messing up the thermal monitoring.

 

[mwhidden]

Best answer selected by mwhidden.