Ok I got this IBM machine when I try to turn on, it turns on for half a sec and then it turns off. It will just keep on trying to do the same thing if I leave it without unpluggin the power. First I thought the PSU was bad, so I changed that but that wasn't the problem. I tried to change RAM as well... could this be the motherboard problem? My assumption is it is but I do not have another motherboard to test it out... anyone had/have similar problem? Thanks

It 'could' be the motherboard, but I would suggest disconnecting everything from it to make sure.

It's hard to say, but if the psu went bad it may also have damaged the motherboard. Look for any visible signs(blown caps) Pull all Card,Devices leaving only psu,cpu/fan and ram to get post codes or beeps. For best help always give System spec.

I don't think the PSU is bad though. No blown caps, I took out all the cards already but same thing. Swapped both RAM/CPU too, but still the same issue. I dont' wanna conclude its the motherboard : (

bit of a longshot this. My experience of IBM desktops is when you connect the power cable the system fans/lights come on for one second and then go off (and then you press the power button to start as normal). I do not know why they do this but it might be that it is checking something like all fans are connected and working, so I would check all fans (including case fan if one) are connected and move when you plug the bable in. I am kind of guessing that this one second stage is it trying to verify something eg. fans are in good order.

Yes I notice that IBM does that. I think that's to check the power and stuff. But in my case its different when I press the power button, it just turn off itself after a half second. I did another test and I found out something if I took out the CPU and turn on the computer, it looks like it runs fine all the fans turns on and start spinning. It can't be the CPU issue becacuse I put in another working CPU and tried.