Motherboard wont POST. Can't figure it out.

Soldato
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I had an Asus Sabretooth 990FX motherboard with an FX-8350 CPU. I've just replaced it with a Gigabyte Gaming SLI AMD 990X.

CPU and other fans come on and spin. My USB keyboard lights up the capslock, numlock, et al (but is otherwise unresponsive and will not turn them on or off - they're just perma-on). However, the Power LED does not illuminate and no beeps are forthcoming telling me what's wrong.

I have an R9 285 plugged into the first PCI-E slot for graphics (nothing is output to the monitor) and connected only an SSD by SATA. There is also an M2 PCI-Ex4 SSD attached which is fresh from its packet. I haven't tried removing that, yet. All four memory slots were populated. I've tried the following:
  • Swap in a different power supply
  • Remove all but one memory stick
  • Swear profusely at it
  • Check and double-check the Power and Reset pins are correctly plugged in (I don't think this can be wrong as the fans start up when I press the power switch and shut down after holding it in for five seconds)
  • Disconnect the SATA SSD and try to post without it connected.

About the only things I can think of left to try are to remove the M2 SSD and to try reseating the CPU which I have put off doing because (a) I think I did it right and (b) it's a PITA. I do have a multi-metre if I have to, though no experience using it with a motherboard.

Motherboard is new and never been used before. This is it's first "go". Everything else worked fine with the previous motherboard with the exception of the M.2 SSD which is new.

Really looking for any advice. It's ages since I've replaced a motherboard. It's perfectly possible I've made some silly error or overlooked something. Help?? :(
 
Associate
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Do you not have the LED post codes showing on the board? - what code does it show?

This would give you a clue as to the problem.
 
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I had a similar issue, try removing the graphics card and see if it posts.

I ended up taking the whole thing apart, reconnecting everything other than the graphics card, it posted fine, shut down, put in the graphics card and all has been fine since. Its always worth leaving the graphics card when you get the machine to post 1st
 
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Soldato
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Right, so... Again thanks for all the replies. To take them in order:

Do you not have the LED post codes showing on the board? - what code does it show?

This would give you a clue as to the problem.

The power LED does not light and the speaker does not sound. I actually got a "motherboard testing kit" (their term) from an electronics shop yesterday which consists of separate beeper, switches and LED entirely separate from the chassis to rule a couple of things out. The Power LED is plugged directly into the motherboard and does not light no matter what I do. Similarly, the beeper has never made a single noise. Whatever is wrong, it's something that seems to prevent the motherboard from "turning on" despite that the fans spin up and the USB keyboard lights are on. (Incidentally, they come on regardless of whether I press the power switch or no, so I think it just indicates that there is power more than anything else).

Tried a CMOS wipe? Does the old motherboard work with all the stuff connected?

The old motherboard worked fine though I haven't swapped it back in since I put this one in so if I somehow fatally damaged something in the move, I wouldn't know it. If I'm forced to, I'll put the old motherboard back in place and send this one back.

I had a similar issue, try removing the graphics card and see if it posts.

I ended up taking the whole thing apart, reconnecting everything other than the graphics card, it posted fine, shut down, put in the graphics card and all has been fine since. Its always worth leaving the graphics card when you get the machine to post 1st

This is good advice. I recall having some "fun" getting a graphics card to run on the old system As I recall it would only run on the second PCI-E slot (another reason why I suspected my old motherboard to be buggy). I've followed your suggestion and removed the GPU entirely. It still wouldn't activate the Power LEDs or POST (obviously I wouldn't see it on screen but I would expect a beep and the LED to come on). I also tried the GPU in the other x16 socket with no different result.

Try building it outside of the case on a non conductive surface.

I can try this. Though the entire thing is currently on a wooden table.

There's something critically and fundamentally wrong here. No beeps, no power LED light... I thought maybe the power connection for the CPU (the smaller eight-pin one that's seated next to it) had maybe failed on my PSU because I had to pull it a little to get it to connect, but with the other PSU it made no difference.
 
Soldato
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Well, I'm out of things to try. Regretfully, I'm going to have to send this motherboard back unless anyone has any other suggestions. Disappointing as this has wasted quite a lot of my time.
 
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have you tried everything back in the sabertooth board built up outside the case?
I managed to screw my 8350 when I bought a new case all I did was move all my components into the new case and the 8350 never survived the move.

I tried a spare board I had sitting with the 8350 that never worked. I then tried an old 1090t in my board and it booted up.. I managed to get a replacement 8350 through warranty by luck.
 
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Well h4rm0ny, looks like the board is 'dead' from what you say - but I would first try the old board again to confirm - obviously if your old board works, then the new one is toast unfortunately.

So frustrating!
 

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Soldato
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I would triple check everything from trying one bit of ram in every ram slot separately, making sure cpu is in correctly, different psu it's rare but some ram models just wont post a board on early bios too
 
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