I recently aquired an old PC from a friend (P2/233) and carried out a few minor modifications to it. Everything was working fine until I switched it on this morning and there was no power. Just
dead.

My first reaction was that that the PSU (which is about 4 years old) had finally gone down. I have a new PSU and fitted this unit but the machine still appeared to be dead. However I noticed that when the power-on button on the front panel of the case was pressed a little spurt of power would apparently go through to the fans and they would turn a few times before stopping. I changed the PSU back to the old unit and the samre thing happened again! In fact if I keep on pressing the on-button I can get the CPU fan to keep spinning! But still no power to anything else.

Does anyone know what is the cause of this problem?

Maybe the power-on switch is worn out or defective. If so will I have to get another case?

Thanks, Alan

Is the PSU's fan turning?

most likely a dead motherboard.

other causes maybe the reset cmos jumper has been turned on, maybe the reset button is stuck?

Thanks for your reply.

The PSU fan as well as the CPU fan will spin a few times when the power-on button is pressed. But nothing happens beyond that.

I checked the reset button and it is working normally. I have kept away from touching any jumpers as my friend lost the M/B manual.

The M/B could be dead but considering it was working perfectly yesterday do you think that is likely?

Regards, Alan

yes, likely since it's old.
Blow all the dust away and try again, but it's probably dead.

oh, come on!!! First off this is an ATX motherboard or an AT motherboard. Judging by the processor, I'm assuming AT motherboard and PSU:

Find the reset button cable that attaches the motherboard. Remove it!
That'll solve that possibility.

Second, do you have a spare power button. Radio shack sells them for less than 10USD. Just be careful hooking it up. Search online for proper wiring. It's four wires and they fit specifically. By the way, a spare power switch isn't a bad thing to have, even if that's not the problem.

Third, look on the board for a product number! Try to google.com it. I have a few older motherboards that when I reconfig them, I check online for the manuals. Many MB companies post manuals online to avoid shipping you copies.


Edit:also, unhook powersupply from all internal stuff (mb, drives, fans) and push the button. If the psu fan works, the psu isn't dead, yet. Hook one thing at a time to it: fan! does it work? if yes: Drives? MB? Work from the bare bones aspect
/Edit

Check power connections.
Other than that, I am spent for now. If any of this helps, click that affero button