First boot, everything works, but CPU getting no pwer, please HELP!!

yiplong

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Oct 22, 2009
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I am putting my computer together and I have a problem here.
I am booting the build in a cardboard box, on the mobo I have CPU & HSF, RAM, video card. When I turn the power on, the video card fan spins, but not the CPU fan. I then connected the CPU fan to a different power source on the mobo, and it worked, so the fan is not the problem.
I turned on the monitor, the gigabyte logo screen is displayed and then it goes into some other thing that I don't recognize. The build does not post.

Since the CPU fan is working, but won't spin when connected to the CPU_Fan power source, it appears that the CPU is not getting any power. (I touched the area right around the chip, and it doesn't appear warm.

The CPU is powered by the 2x4 12v ATX power connector right? To that I connected two 2x2 wires, marked "CPU1" and "CPU2". I tried plugging them in different ways and found that they only go in one way.

Can someone please help me troubleshoot this?
 

a4mula

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Which model of Gigabyte do you have? What psu do you have? You also didn't mention the 24 pin main connector...

cpu1, cpu2 are more than likely 4pin fan connectors.

Some mobo's provide secondary 8pin cpu power in the upper left hand corner.
 

That doesn't make any sense. Your CPU is getting power just fine if you can see the Gigabyte screen. I would guess that the "other thing that I don't recognize" is the BIOS. You need to set the boot priority to your CD/DVD drive as the first device and then reboot with your OS disk installed to install the OS. Seems like business as usual to me.
 

yiplong

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Indeed you are right. Everything is actually working just fine. The reason that the CPU fan will not spin when connected to the CPU_fan connector but works fine when connected to a different connector is because this fan is a 4-pin fan and fan control is enabled by default in BIOS. I guess my CPU temp was below the theshold, so the fan didn't kick in. :wahoo: :wahoo:
I thought fan control would only switch between low/high speed, I had no idea it would totally stop the fan. I guess you learn something new everyday.