I have a few motherboards floating around at any time.

They are useful if I need to make up a cheap second hand PC for a customer. I also happen to have 3 identical motherboards(d865glc), that are also the same as my main system… OK, a pentium 4 system is getting a bit old by todays standards, but it works well for me.

A while ago, I used a d86glc to make a second PC at home.

It worked well for a few months, then I needed to mothball it for a few months.

A few days ago, I needed it again, so I started it up again (it started OK), and left it running updates while I went out for a few hours.

When I came back, the PC was off.

Thats strange.

Anyway, hit the power button, and the lights come on for a few seconds, then go out.

OK, maybe the power supply has had it, so I plug in another PSU, only to see the same symptom: PC starts for a few seconds, then stops.

OK then, the motherboard has died. So I dig up one of my 2 spare (identical) motherboards, and being paranoid, I first connect it to the new power supply thats currently on the bench… It starts OK.

Good, now I swap motherboards, and connect everything up again, start the PC, go to the bios and check the settings.

I’m almost finished adjusting the settings, when the PC suddenly stops… all power is lost.

Hmmm, can I have a faulty motherboard and power supply? Highly unlikely.

Maybe the RAM? I pull out all the RAM, unplug all drives, etc, switch on, and the PC beeps (its saying it wants RAM)… OK, I plugin only 1 stick or RAM, but the PC won’t start.

I swap RAM sticks, and this time the PC starts… aHa, maybe it was just faulty RAM causing startup problems.

OK, back to the bios again… and again, I lose power before I can save any BIOS settings.

Whats going on?

The original motherboard won’t work with the new PSU, so I’m sure the motherboard is stuffed.

But why would the “newer” motherboard also fail?

I try swapping and reseating everything (including CPU), but nothing seems to work.

I sleep on it, and the next day, I decide to try the third motherboard on the bench with the new PSU… it works.

I plug the RAM into a test PC, and do a memtest… the RAM has no faults.

OK, I now plug the 3rd motherboard into the first PSU (thats still in the case). Nothing happens…

Hold on! As my fingers brush past some mobo capacitors, I sense some heat.

Capacitors shouldn’t heat up like that.

I cut all power to the PC, and check the mobo… the wires that go to the 12V, 4-pin plug on the mobo are also quite warm… a lot of components in that area are warm… why?

I decide to test the first PSU… I rig up my multimeter, and I expect to see the typical 5V and 12V, but instead I see values shifting between 100 and 230 Volts !

Maybe I’m having a bad dream… I plug the multimeter into the new PSU, and the voltages are normal… back to the original PSU: more high voltages.

My heart sinks: The semi-faulty power supply just fried 3 motherboards in less than a day.

Damn you, bastard power supply from hell!!!