Troubleshooting new PC that won't POST

[skyhawk04kilo]

I'm assembling a budget PC. I bought new parts except for the motherboard and CPU, which were both from eBay.

- MSI B250I Gaming Pro AC mini-ITX board
- i3-6100 CPU
- Stock cooler from my i7-4770K (seems to fit fine)
- GSkill DDR4-2133 (2x4GB)
- Corsair CX450M PSU
- Cooler Master Elite 130 case

When I first plugged in the PSU and flipped the rocker, the fans started going and a red light with "CPU" next to it lit up. MSI documentation calls this "EZLED", used for troubleshooting. The other lights are all off. Pressing the power switch does nothing, holding it down does nothing. The monitor shows nothing when I flip the rocker switch, and it works correctly when I plug in my laptop.

I've re-seated the CPU, tried a single stick of RAM in both slots, tried no RAM at all, cleared CMOS, tried a different power supply, tried unplugging all of the front panel connectors, everything gives me the same results - the fans and CPU light turn on with the rocker switch, but nothing else happens.

I'm pretty sure either the CPU or the motherboard is shot, but looking for advice on any other troubleshooting that I can do to narrow it down to CPU vs mobo. I don't have another processor that will work in this motherboard to try.

 

[lumineZ]

Take the CPU out and look very carefully for bent CPU pins on the motherboard.

 

[skyhawk04kilo]

Take the CPU out and look very carefully for bent CPU pins on the motherboard.

Thanks for your input. I did check this when I re-seated the CPU and did not see any bent pins.

 

[lumineZ]

- Triple check that all cables are connected correct and plugged all the way in.

- Do you have a spare PSU laying around or maybe you can borrow one from a friend to test that it is not your PSU.

- Make sure you are not making a short circuit. Like the back of the motherboard somehow touches the motherboard tray etc etc.


Question:

Did you do a build outside the case to test that everything works? (always do this before mouting everything into the case)

 

[skyhawk04kilo]

- Triple check that all cables are connected correct and plugged all the way in.

- Do you have a spare PSU laying around or maybe you can borrow one from a friend to test that it is not your PSU.

- Make sure you are not making a short circuit. Like the back of the motherboard somehow touches the motherboard tray etc etc.


Question:

Did you do a build outside the case to test that everything works? (always do this before mouting everything into the case)

I did not do a test build outside the case. I've built 3-4 computers so far and never ran into a problem, so it didn't occur to me to do that. I've just taken everything out of the case. I've got the motherboard with the CPU, cooler, and 1 stick of RAM on it, and the PSU sitting next to the motherboard on a wood desk. Same results. I did pop out the CPU and checked the pins with a macro lens on my camera and none are bent.

The mobo was 'new in box' on eBay but the CPU was not. So I'll try a new used CPU to see if that works. Thanks for your suggestions.

 

[lumineZ]

Hmm. Since you have bought a used CPU there is a slight chance its broken... But impossible for me to say.

 

[skyhawk04kilo]

Hmm. Since you have bought a used CPU there is a slight chance its broken... But impossible for me to say.

It ended up being the motherboard. I returned it for another used one off eBay and everything is working perfectly now. Thank you for your help!