I built a shiny new rig just over a month ago, and everything had been running smoothly, until tonight. The problems started after I had just installed a fan controller. As I was testing out the controller with one of my fans, I noticed that the system seemed to be drawing power in an unstable fashion. Specifically, the fans (that were not hooked up to the controller at the time) were speeding up and slowing down in rhythmic pulses. In addition, the brightness of the LEDs on the board appeared to be changing in intensity along with the changes in fan speeds. I turned everything off and returned everything to its original configuration to see if the fan controller had anything to do with it.
Now I'm having some issues powering up my motherboard. Plugging in the 24-pin ATX allows me to power up the fans, CPU, CPU cooler, GPU, HDD, and CD/DVD drive with no apparent problems at all. After shutting the system down and adding the 12v 8-pin ATX connector to power up the rest of the motherboard's circuits, the board begins boot-up for just a fraction of a second the next time I try to turn it on before immediately shutting down. The fans have just enough time to start spinning before everything stops. The ACPI S5 LED, Power, Reset, and CMOS reset switch remain lit, so the board is still drawing power
I thought it might be a short caused by an errant object in the case or the motherboard standoffs, so I removed the motherboard, CPU, CPU cooler, and GPU and tried starting it up on a table-top. The results were precisely the same.
Pertinent System Specs:
GB EP45-DS4P Motherboard
Intel Q9550 Processor
4 gb OCZ DDR2 RAM
HD 4870 graphics card
Thermaltake Toughpower 850W power supply
I know this is long time ago.
Did you ever fix this? I have exactly the same problem withs 2 yr old board.
If the board is stuffed, then I wont bother taking it to anyone for checking, I'll just have to get another mother...