New build power issues


I am putting a new system together which is giving me a bit of a headache. The system is based on the LGA775 based X7SBL-LN2 motherboard by SuperMicro. The board has a 24 pin connector and a 8 pin connector for powering the board and the CPU. The processor is a Xeon E3110 and I am using a Gelid Silence low profile cooler. The chassis is the 1U SC502-200B from SuperMicro. The challenge is to run the system cool in the 1U chassis but unfortunately I am not quite there yet. I don't plan to use any graphics and therefore apart from 2 memory sticks the only other component is a 2.5 inch disk drive.

I have two power supplies I tested my set-up with. The 200W supply that is coming with the 1U chassis and another SuperMicro supply rated at 260W. What is happening is the following. With the 200W supply and the 20 pin / 8 pin connectors in place the fans will move 1 inch before they stop. Nothing else happens. The power supply stays switched off i.e its fan doesn't spin either. With the 260W supply and the 24 pin / 8 pin connectors in place the fans do not move at all and this supply also stays switched off. This is where it gets interesting. If I remove the 8 pin connector then the fans do not move, both CPU and chassis fans, however the PSUs come to life. Obviously in this case the CPU does not have any power and it is pointless so I switch of the system. What confuses me is that the PSUs do start in this case. What I am thinking is that somewhere in the CPU circuitry that gets powered up by the 8 pin connector there is a short. I am suspecting the CPU cooler.

Needless to say that I tried with the memory sticks out etc and the behaviour did not change. I am also waiting for a 2nd motherboard to arrive to see if it works and if the original motherboard is dead. Going back to the CPU cooler, I have it screwed on 4 thumb screws going from the other side of the motherboard. The cooler is then screwed on those via screws with springs. Obviously both sides touch the motherboard around the holes. I used some plastic o-rings that came with the cooler on both sides of the board. I am suspicious about this. The screws that keep the board in place touch little metallic blobs around the holes for grounding purposes. Do you reckon I need to remove the o-rings? I don't have any reason to believe that any component was defective.

I also tried everything using a Xeon X3210 which I don't plan to use anyway because it is rated at 105W which is too much. The behaviour was the same. I am waiting for the new board but I have a feeling that it won't work either and there is something else going on. Any ideas?

When the power supplies are plugged, the motherboard leds do light up and I can see the ethernet ports flashing once or twice.
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  1. It does sound like it could be a short, or that you have 2 bad power supplies (not able to carry the load they are rated for, not that they are dead completely). Try taking the cpu cooler off completely and starting the computer (leave fan pluged into the cpu fan header) if this makes it come to life the heatsink hookup is your short, and find a way to fix that, and IMMEDIATELY turn off the computer. If not then you're barking up the wrong tree and either have bad power supplies, a bad CPU or bad board.
  2. Just as a note, I did try the motherboard outside the chassis and it was the same behaviour, it didn't make a difference.
  3. Did you try without the CPU hs installed (only plugged into the header?) Once again, if it fires up shut it down instantly, Additionally if you haven't already reseat your processor (take it out and put it back in)
  4. I didn't try without the heatsink for the fear of killing the cpu (if it is not already dead - which I don't think so). Will contemplate about trying it until I get home later tonight. Are you sure it is a good idea? It takes a couple of seconds before things go sour. I did remove the processor and reseated it, new thermal paste, reset CMOS etc. Thanks!
  5. if it makes you feel better just unattach it, make sure its only touching the top of the CPU and not the board in any spot (assuming board laying level to ground, not standing up). and start it. This will still tell if your mounting solution was messing things up, and still supply a little bit of cooling. it won't fry in 5 seconds either way, but if it would make you feel better that will work.
  6. Apparently, according to this

    the motherboard is dead. I bought it as used but working from eBay but now I don't know if I damaged it or I actually got it like that.

    The PSU does not start when the CPU is present, if I remove the CPU altogether it starts but of course nothing else happens and I get an alert (red led light) from the chassis and the motherboard.

    I will wait for the new components to arrive but I am not holding my breath unfortunately.
  7. Yes I'm pretty sure a motherboard and GPU would be the two items I would nearly never buy on ebay, I'd not buy memory that didn't come with a lifetime warranty either, and would only buy if it would cost me less to ship it back to the MFG for replacement than the discount I recieved for getting it used.
  8. Just for completeness, motherboard was faulty. At some point it powered up (to my surprise!) and it fried some circuitry - bad smell and all - underneath the heatsink that is located next to the cpu (I think the voltage regulators and other paraphenalia are there). I replaced it with a second SuperMicro board, same model, and the machine worked fine.
  9. Great to hear that you fixed your issue. Glad your system is up and running.
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