I went to upgrade my motherboard and processor today from an older Asus P5N32-SLI SE Deluxe + C2D E6600 to a new Gigabyte GA-EP35-DS3L + C2D E8400. I have an aftermarket CPU heatsink, a Thermaltake something which is basically just a gigantic tower of copper fins, with screw holes to put on a fan if you need one. Its meant to be able to run fanless. Anyways...
When I hooked up all the new hardware, nothing happened. Lights went on, fans went on, but there was no POST, and no error code beeps. I thought something was fried. So I tried using the old processor on the new board to see what was the problem.
Long story short, I finally realized that the problem is the board will not post if on the CPU fan header, you use a 3 pin connector, like the one on the standard case fan I have mounted on my TT heatsink. It worked on my Asus board, putting only the 3 pin fan connector on the 4 pin header, it would just say "CPU Fan error!" on bootup and I could manually disable that warning in the BIOS. The Gigabyte however, will not show ANYTHING if there isnt a 4 pin connector on the 4 pin CPU fan header.
Is there any way to create a workaround for this? Right now I just plugged in the heatsink fan somewhere else and have a spare CPU fan that I pulled off a stock heatsink hanging in my case. I'd like a more permanent solution. If I need to buy a new fan, OK, but I would prefer it if anyone on these forums knows how to trick the mobo into thinking everything is ok. Thanks!
Hey I recently have had the same problem, except mine is intermittent. Have you had any luck? I just tried putting the stock cooler on the 4 pin header and my installed after-market tower into the cpu_fan, and it booted up to bios. (first time in all my troubleshooting today)
A little history:
I've had this computer for about a year now, worked fine first 6 months. Then my front audio/usb jacks started freaking out. When i touched something to the jacks (even before insertion) the graphics output would quit. (screen would go blank, monitor would go to sleep mode) and I would have to reboot (had to hold the power button in, so I think the computer froze too.) I'm not sure if this is at all related to what follows, but just in case.
then about 3-4 months ago it would freeze before POST, no beep codes, during startup. This first happened when I lost power to my house. It seemed to only be a problem when the power was disconnected, ie, a soft reboot from windows would be fine. When it froze, i would just keep hitting reset till it worked. When it first started, i would only have to reset once, and then it would boot normally. Then it started taking more and more continuous resets. Eventually around 20. I tried unplugging some stuff from the back of the computer, but did not notice any pattern (though there could have been)
Finally I pulled it apart and put all known-good components from an older Dell in, stripped down to the cpu, heatsink, 1stick mem, and gpu. Same problem, so i concluded that it was the mobo. Sent it to gigabyte, they did something, sent it back, and it was like just setting the clock back a month or two. it was back to taking 5 resets to boot, which quickly (time frame of a few weeks) returned to the 20+ resets to boot. I sent it back again and complained enough that they sent me a replacement. This board hung at the exact same spot first boot up (with original components). Occasionally I was able to get to the bios, but with no discernible pattern from my unplugging this and that and so on. New issue, when i got to the bios, after about 2-5 minutes it would freeze IN THE BIOS... I would have to actually unplug from the wall to restart; power/reset buttons did nothing. Also sometimes when I try to start i'll hit the power button (or touch the power jumpers with screwdriver, depending on what i'm testing) and will count to 20 before the lights/fans come on and it hangs... ???
It is doing variations on all this as well, again reinforcing the fact that there is no discernible pattern that I can find as to what might be causing the problem.
I stumbled across this post (which no one replied to... ) and to be honest, this fix doesn't make sense to me, especially since my build worked fine for 6 months, and didn't show this particular no-boot hang for about 8-9 months. But I just tried it and got to the bios, so I will be doing some more testing tomorrow. Hopefully either you or somebody can reply with some insights or something.
E8400 stock speed
PNY XLR8 Performance Ed. Nvidia 8800GT 512MB stock speed
2X1024MB CORSAIR DOMINATOR XMS2-8500 (1066MHz) stock speed; upgraded with another 2 of same sticks when I got the replacement motherboard
TUNIQ TOWER 120 (3pin)