System Fails To Post, CPU fan runs full speed for a few seconds, then slows down for a minute and runs fullspeed again/repeats

Im a new system builder, So its very possible I have made a incredibly stupid mistake, but I have worked through the troubleshooting guide with no success.I have made a breadboard with just cpu, cpu fan and memory. I have both the 24 pin header and the cpu power connector connected. When I start the system the cpu fan twitches 3 or 4 times, runs at full speed for a couple of seconds and then slows down for another minute after which it stops, twitches 3 or 4 times again and runs the at full speed for a couple of second and repeats everything.

I have made a youtube video to help show you guys whats happening:

I want to blame myself before I go blame components but I ordered the motherboard from a dodgy vendor online, because they were one of the only vendors to offer this motherboard. The package of the motherboard came unsealed and the package itself was in a poor state. The anti-static bag around the motherboard also had no sign of a seal. For all I know this motherboard could have been used already. The back of the motherboard is also sticky for some reason.

I would be ever so thankful at any attempt to help me! cheers!
7 answers Last reply Best Answer
More about system fails post cpu fan runs full speed seconds slows minute runs fullspeed repeats
  1. Looks like a dead mobo to me bro. Why is it not sealed? Because they might have tested it first to make sure that it works. BUT why is it sticky? That is weird.
  2. Best answer
    CheCk a few things. Look on the mb for the bios rev sticker. Make sure the bios on te mb now will post your CPU. Try another test power supply and one dimm. Sometime if the bios needs an update it post with one dimm not two.
  3. Thanks guys for your suggestions so far, the cpu is a i5-4670k and the mother board is asrock z87e-itx which is supposed to support the CPU from from the first bios. I Tried using only 1 memory stick in each slot and that dident work either :(. I would greatly appreciate any further assistance you can provide me.
  4. I really believe it's your mobo's fault bro.
  5. I did some further testing and found out that it seams like the psu fan stops turning before the cpu fan by a second or two. Its a silverstone sfx bronze 450w that came with the sg06. Does this symptom indicate anything special or is it still likely to be the motherboards fault?

    @adimeister, me too, but before I send it back and have to wait 2-3 weeks for a new board I would just like to make sure that its 100% the case.

    EDIT: I dug through my entire attic to find an ancient hp pc to test my PSU on. I plugged my PSU in this computer and booted it and everything works fine. So the PSU is definitely ok. THis means either the mother board is broken or the cpu. Im going to take your advice and send in the motherboard.
  6. One thing try the mb outside of the case to rule out a dead short.
  7. Ok got motherboard replaced, Tried everything on breadboard. Still same problem. Interesting thing im noticing is that when I connect cpu fan header to chassis fan it doesent go full speed. So do you guys think the cpu is faulty?
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