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System fans turn on automatically when power supply turned on..no post

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So, I have a new system that I'm currently building...everything seems to be placed correctly. The 24 pin adaptor and both 8 pin adaptors (dual processor system) are correctly placed from the power supply to the motherboard. Video card and ram are placed correctly. However, this is a problem I've never seen before. With a plugged in power supply, I turn the power supply on (on the back of the psu), and then about 2 seconds later the CPU heat sink fans (plugged into the motherboard) immediately turn on...
About 2 seconds after that, a light comes on on the motherboard, showing that it is receiving power (according to the motherboard manual, this is what LED1 shows). When I try plugging in a SATA HD, it also begins it's internal spin up procedure. However, I get no beep codes of any kind. I don't see any comments on this error in the sticky thread above. I've attempted removing both the Power and Reset SW (thinking one of them might be shorting, but the system still automatically turns on with both of them disconnected.

The board is a supermicro X8DAi-O with two xeon 5520 processors. The graphics card is a Geforce 9600 model (PCI-X), and the power supply is the Corsair 850W Modular power supply

Any help would be appreciated,

~Lyuokdea

More about : system fans turn automatically power supply turned post

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Motherboard Expert

1) Have you stand-off's between the motherboard and case/tray?

2) Is there anything that could be shorting the PWR pins on the underneath side of the motherboard. Like a stand-off in the wrong place?

Have you cleared your cmos?

Can you try turning the computer on by shorting the two power switch pins? (a small screw driver or paper clip should do the trick, just make sure you are shorting the correct ones)
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Update....

Still going through steps on the guide. I removed all system RAM, and started the system....I correctly got the "No System Memory" Beep-code. The system again started automatically.

But, unless I'm mistaken, this seems to rule out a couple of things, such as a shorted restart button (because it would never get through the beepcodes) as well as most problems with the motherboard power supply. There seem to be two problem now, one which is causing it to start up automatically. And one which is causing it to not post...

What would cause it to not post without any beepcodes, if it can correctly get to a point where there are beepcodes?

Thanks

~Lyuokdea

And more interesting updates...

with one stick of memory in, but the video card removed. I do NOT get the no video card beep code (there is no onboard video card)

So the error seems to have something to do with memory, but I've tried two different sticks in two different locations, and that doesn't seem to fix the error

~Lyuokdea
Motherboard Expert

Unplug, from the motherboard, all the wires that go to your front panel.
Does the PC still start on its own when you switch on the Power Supply?

Edit: (UnPlug all the wires that go to the front of your case)

knotknut said:
Unplug, from the motherboard, all the wires that go to your front panel.
Does the PC still start on its own when you switch on the Power Supply?

Edit: (UnPlug all the wires that go to the front of your case)


yes... it automatically starts up with absolutely nothing connected to the front of the case....


i notice that the bios lists that there is an option to allow this (probably to allow automatic restart after a power outage since this is a server board?) This option is supposed to be disabled by default though.

~Lyuokdea

Outlander_04 said:
is this an MSI mb?

do they actually use beep codes? Have you connected the case speaker ?
what does the manual say?


It is an ATX board, and has beep codes, and the speaker must be somewhere on the MB somewhere, because i never installed anything, but it is working (getting beep codes when the ram is not installed)

~Lyuokdea

More updates....

The system has 12 DIMM slots...(6 near each processor), the manual specifies that you fill 1A1, and 2A1 first (their notation). This is what I did the first time, and cause the no post. However, loading 1B1 and 2B1 first causes the same no-memory beep code that you get if no memory is installed. This makes sense, but might point against the memory shorting the system.

Also tried to intentionally short the power button when the system was on, to see if it would turn off, it wouldn't in either memory error or no post mode.

~Lyuokdea

DaMAn42 said:
That sounds like a dead mobo....


Would that explain the automatic turn-on error though? Also, what's the likelyhood that a dead mobo correctly notices the lack of ram and posts the correct beep-code?

Thanks,

~Lyuokdea

Also, if I try to breadboard the system, can I use the styrofoam backing that came with the mobo to put it on? Or is that electrically conductive? If not, what should i use?

Thanks,

~Lyuokdea

Anything else I should be trying before I RMA the motherboard? I'd hate to wait 5 days for a turnaround, only to find out it's some other problem.

Thanks,

~Lyuokdea

Well, i cleared the CMOS, and that seemed to fix the automatic on problem (after I then shorted the power button once to turn it off)

It now correctly turns on and off, but does not post...

I took the motherboard out and checked to make sure I didn't leave an extra copper stud anywhere, but i didn't, so it shouldn't be any random shorting problem

I guess we're narrowing it down towards bad motherboard, the next step, i guess, would be to try running it with only one of the two CPUs installed. to test for a bad CPU.

~Lyuokdea
Motherboard Authority

Been reading through the thread here.
You most likely have a problem in 1 of 3 places.
Memory...it is possibly not compatable with your board. This is more common that most people think, and is usually the culprit when a new build will not post. I often wonder how many boards get returned as bad when the memory was actually at fault, I would guess 8 out of 10 of them. And the memory may not actaully be bad, some boards can be picky about memory.
PSU, yes just because fans, lights, and drives spin does not mean your PSU is working correctly. I just recently experienced this very problem with my build. This too, is a pretty common issue.
Motherboard...it MIGHT simply a bad board. This....or a bad CPU are the 2 least likely things that happen. CPU's especially are very, very, very seldom bad.
I would not however jump to the conclusion it is a bad board until you have tested the memory and PSU parts.

And, remember with all electronic parts, just because something is brand "new" does not mean it cannot have something wrong with it.

Good luck!

actually....&%$&*#, maybe registered motherboards won't take unregistered memory? The common sentiment when I asked earlier was that it would, but maybe that was a mistake

~Lyuokdea

Can anybody back me up, and confirm that you can't use unbuffered memory in a registered motherboard? If so, that seems to answer the problem correctly (now that the problems with the board instantly turning on have been resolved). Unfortunately, there's no way to go buy a stick of memory today to test that (since I doubt anybody local carries registered ECC DDR3)

So I want to confirm this is probable before I trade in and beg newegg to waive the restocking fees.

~Lyuokdea

Can anybody confirm that this problem is likely do to having unbuffered ram in a registered slot? I don't want to go and purchase a couple hundred dollars worth of new components, to find out that it's a busted mobo

thanks,

~Lyuokdea

Well, supermicro seems to believe that the RAM is indeed good. This leaves the power supply and motherboard as the two possible power components. But I don't have an extra of either, so it's hard to determine which is at fault.

I'm going to try to pull out one of the processors, and run the motherboard with only one processor (I believe this will work ok?) But I can't figure out anything else to do for the life of me.

Anything else I should check? Should I try RMAing both components? Should I only RMA one?

Thanks,

~Lyuokdea

If you pull one processor out of the dual processor array, do you still put in both 8 pin 12V lines to the motherboard? Even though one processor isn't there to receive the power?

~Lyuokdea

nickhoff said:
Sounds like you have the RAM in wrong. It should be in A1, B1, C1. A1, B1, and C1 are the colored slots. I'm guessing you put it in closest to the CPU.


No, I've put it in the colored slots. When I put it in the black slots as a test, i continue to get the memory beep code, instead of getting the system to hang, so there is definitely something different about putting it in the blue DIMM sockets (which should be correct) as opposed to the black ones (which should be wrong)

~Lyuokdea
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