[SOLVED] System won't start at all, even after replacing both PSU and mobo

Jan 26, 2019
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I had an MSI h110m gaming motherboard, and I had just gotten a new gtx 1070 when problems started. GTX 1070 would not give video output no matter how many times I reseated it and tried different cables, so I checked that both onboard video and my old GPU still gave video output -- they did. After switching back to 1070 and reseating more it suddenly stopped turning on, as in hit the power switch and no fans spin, nothing.

I tried flipping around the power switch header from my case a few times, no difference. I tried plugging the PSU into another AC outlet, nothing. I tried shorting the motherboard and I could not short the motherboard at all, I tried two different screwdrivers (one phillips, one flat headed). I tested the PSU with the paperclip test (with PSU only connected to a hard drive), and it powered on.

I assumed the motherboard was dead if I couldn't short it and it wasn't the PSU and ordered a new motherboard (Asus H110M-E) and installed it in my case. Same exact symptoms, tried same things. Nothing would get the gpu to turn on. I tried the paperclip test on my PSU again and it did not work this time.

I RMA'd my PSU (an EVGA 600w 80+ model). I originally was going to install the system with my old MSI motherboard first, in case it was only the old PSU that was bad and I could potentially get a refund for the ASUS motherboard, but I discovered that my MSI motherboard's cpu socket had a bent pin. I don't know when this occurred, I've ran the system fine for 2.5 years since I originally installed the cpu and hadn't touched it since I took it out to put the cpu in my new Asus motherboard.

I installed the new PSU with my Asus motherboard and the same symptoms persisted. No fans, no power, nothing, power switch would not work, shorting would not work. I breadboarded the system, placing the motherboard on top of it's box, with two sticks of ram installed (same model for each, 2x8), my cpu, my cpu heatsink plugged in (but not mounted), the 4-pin CPU cable plugged in, both GPUs at various points with the PCI-E connector plugged in, and of course the 24-pin cable plugged in to the motherboard.

Breadboarded it still will not work. I cannot short the pins on this motherboard still (I even took off the heatsink's backplate thinking perhaps it had come loose and shorted the motherboard somehow). I performed the paperclip test and while it was a little wonky (sometimes the PSU would stop turning on and I'd have to reseat the paperclip fresh to get it to work), I tested it multiple times and it would only ever turn on with the paperclip when it was only connected to the hard drive (with the psu and hard drive powering on and spinning). When I connect the PSU to the hard drive AND the cpu 4-pin power, it does not turn on with the paperclip test.

Something that did not happen with the original motherboard and PSU was that my old GPU shows that it is getting power from both the pci-e lane and the pci-e cable. It was not doing that before, but with this PSU and motherboard combination it does. The 1070 doesn't seem to have a power indicator.

TL;DR: I have NO idea what is wrong with this thing. I don't know why the board seems to be receiving power (at least to the GPU), will power on with the paperclip test when with a hard drive but not with the cpu 4-pin and hard drive, and why I cannot short the power pins. I have checked that they are the right pins multiple times, I've tried the other pins, nothing sparks nothing happens. It's as if the board is not receiving power but I'm pretty sure that it is..

Please help. I apologize if this post is too long -- I just wanted to be thorough.
 
Solution
You need to take the motherboard out of the case and test with minimal components installed, on the bench, desktop or countertop.

Read the whole guide VERY closely, because there may be a specific factor involved. Make absolutely certain that all of the motherboard standoffs installed in the case are ONLY where there are standoff holes in the motherboard, and I'd triple check the CPU socket for further bent pins.

I'm almost betting you have a failed CPU, possibly due to the bent pin you saw on the other motherboard, but testing is where you need to start.

Also, you shouldn't have any drives or drive cables, at all, connected when bench testing unless it has already been able to POST without them connected.

TLDR, nothing except the...
You need to take the motherboard out of the case and test with minimal components installed, on the bench, desktop or countertop.

Read the whole guide VERY closely, because there may be a specific factor involved. Make absolutely certain that all of the motherboard standoffs installed in the case are ONLY where there are standoff holes in the motherboard, and I'd triple check the CPU socket for further bent pins.

I'm almost betting you have a failed CPU, possibly due to the bent pin you saw on the other motherboard, but testing is where you need to start.

Also, you shouldn't have any drives or drive cables, at all, connected when bench testing unless it has already been able to POST without them connected.

TLDR, nothing except the power supply, CPU, CPU cooler and memory should be installed when you FIRST try to power up on the bench. Then, connect mouse. Then, connect keyboard. And so on.



As far as the post being too long, jeez, I wish everybody would offer that much detail. It would sure make things easier for us all.
 
Solution