GA-K9N-SLI Motherboard (not the Pro or Ultra)
AMD 3200 64 bit processor
250 Gig PATA HD
Two 1 Gig RAM
Geforce 7600GT (FORSA)
WinFast DTV 1000T Tuner card
I have had a new system for about 8 months now. No problems until about 2 weeks ago when my computer froze, the graphics on the screen turned to lines, the video card fan increased in speed while the CPU fan stopped and a weird fizzing noise came from the motherboard. I also couldn't turn the computer off via the switch on the case or reset. Having completed a windows update prior to this I thought (for no real reason) that this was the problem (driver issues maybe).
I downloaded speedfan to montor all temperatures and did a system restore to 2 days prior to the problem. All temperatures fine for two weeks and no problems until it happened again (coincidently after another windows update, the same one which you can do with the option of turning off the computer and installing the updates while it shuts down).
It hasn't gone this time, having changed all other hardware on system with no hard drive connected (borrowed my brothers stuff). Only have the RAM, CPU and videocard in system (all which have been changed with brothers similar hardware) and the problem still happens. also changed power supply.
It will happen even in bios. It occurs after approx. 2 minutes and then after 15 seconds when the computer is turned straight back on. If the computer is let to sit (5 minutes) it will occur after two minutes again (i can get into windows fine if it is within the time frame).
I have already tried the latest bios update, still not fixed. Will be taking the MOBO back to the shop as still under warranty, thought id make sure there is nothing i can do to fix it before i do.
I inspected the motherboard but nothing looks wrong (ie burnt or anything coming apart).
Have you tried another CPU fan. Sounds like the fan could be intermittently shorting causing excessive power draw which in turn causes system to shutdown. It's not a good thing when your motherboard makes noise. I would see if another fan fixes the problem. With it making noise like you describe, something is shorting. Make sure any extra molex connectors (hell all connectors) from your power supply are not touching anything metal. Even though the pins are female and recessed in the connector body, it is still possible that if they are pushed up against a corner of metal, they could be shorting out. Also check to be sure the ATX power connector is fully inserted. You could also remove the ATX connector and make sure that all the pins are fully inserted into the connector. Those molex pins have been known to come loose. When you assembled the computer, were there any unused stand-offs under the motherboard? If there were, these should me removed as they could be shorting out on the back side of the motherboard. If something is infact shorting, you could always try to start your computer up in a dark room. If something is sparking you may be able to locate it by the flashing that occurs during arcing. If none of this helps take the motherboard back like you said and get it replaced.
The CPU fan will stop about 10 seconds before it crashes. So I decided to change the CPU connection to the System Fan connection on the motherboard and it works perfectly with no problems. Is this dodgy? Does this make any sense?????
It could be that the CPU temperature fan control on the motherboard isn't working properly (motherboard normally tells the CPU fan to slow when the CPU isn't in use, could be completely stopping it instead?).
Now that I know the CPU fan will work in Sys fan on MOBO i will put the computer back together and monitor the CPU temperatures and fan control in bios.
The CPU fan is fine as I already tested my brothers exact same CPU with fan and still got the same problem (when using the CPU fan connection of motherboard).
Thanks for the help though techgeek. I tried the mobo in the dark while it stuffed up but saw no spark. I have also tested the mobo out of the case on a sheet of cloth and still got the problem. I also completely changed the powersupply, and still the crash.
Any ideas on why my CPU fan connector would be doing this?
If the fan doesn't work on the CPU fan header, I would take that motherboard back. It's not that it really matters where your fan gets powered from, but the idea of accepting (working around) something damaged when you can get a replacement wouldn't sit well with me. You seem to have logically eliminated everything else, I would just demand a replacement.
It is fine if I have a large room fan blowing into the case, so I am guessing something is overheating on the MOBO, even though temperature detection programs arent picking it up. I dont think there is much else I can do except take it back now.
Anyone that cares who has this same problem, i found someone who experienced the same thing and my "nForce bridge chip heat sink" on the MOBO is very hot to touch too! Looks like i need to get a big fan to cool it.