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CPU fan spins half-second, stops, no beeps


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#1
Dr. Vick

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Some things I might have done wrong:

Too much pressure on the CPU socket cover. Maybe bent a pin or otherwise damaged the CPU or motherboard.

Too much thermal paste. (It doesn't seem to have gotten anywhere it shouldn't.)

Sat the motherboard on top of an anti-static bag at one point. (Stumbled across a post saying not to do that while searching for tips on this CPU problem.)


I'm wondering if there's anything else I can do to diagnose this. The CPU was ~$300, the motherboard ~$125. I think it will cost at least $60 to have a PC repair shop test the components. I don't want to risk breaking a second PC by mix-and-matching the parts myself. I'd like to identify the problem and resolve it for the least amount of money--maybe everything works, even, and I've just overlooked something.

The sticky post here says to plug in both the 20/24-pin and 4-pin power supply cords.

If you have only a 20/24-pin cord plugged in, could that cause the CPU and CPU fan to not get power?

All other fans, including the fan on the graphics card, all power on. All other LEDs light up. But the CPU fan only moves for a half-second on power up, and the LED on the CPU fan doesn't come on. I tried powering on with the CPU fan unattached and the CPU did not become warm. (I know it's a bad idea to leave the PC on for any more than a few seconds with no heatsink/fan attached. Let me know, though, if this diagnostic step is unhelpful. I've read that the CPU quickly overheats--even within 10 seconds--when powered on with no heatsink/fan, so I reasoned that if the CPU doesn't even get warm then it must not be getting power at all.)

Motherboard: GIGABYTE GA-EP45-UD3P LGA 775 Intel P45 ATX Intel Motherboard
CPU: Intel Core 2 Quad Q9650 Yorkfield 3.0GHz 12MB L2 Cache LGA 775 95W Quad-Core Desktop Processor
PSU: ATX-CW500P4 500W TurboLink ATX 12V

I tried plugging the 4-pin cord from the PSU into the righthand side of the 8-pin port on the motherboard, which the manual seems to indicate is the right way to plug it in (and it's the only way the cord will fit into that port). When powered on then, the CPU fan moves for a half-second as before, and then EVERYTHING goes out--all lights and LEDs. This is with the CPU fan not screwed into place but just sitting on top of the CPU. (I don't see how it could make a difference, but maybe it does.)
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#2
Ferrari

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This is a quote from your motherboard manual...

Use of a power supply providing a 2x4 12V power connector is recommended by the
CPU manufacturer when using an Intel Extreme Edition CPU
(130W).

Though you processor may not be the "Extreme" edition of a Core 2 Quad, it is a very high end Core 2 Quad. Or did you mistype??? Do you have a QX9650 or a Q9650? The QX is the 130watt processors the manual is talking about.

From what you have said, the manual suggests that a 4pin connector plugged into the correct part of the motherboard will work, but I don't know if that is advisable. I would think a PSU with a 8 pin connector would be best and may solve your problem.

However, and also, your manual says this...

The ATX_12V_2X4 power connector is compatible with power supplies with 2x2 12V power
connector. When using a power supply providing a 2x4 12V and power connector, remove the
protective covers from the 12V power connector and the main power connector on the motherboard.
Do not insert the power supply cables into pins under the protective covers when using a power supply providing a 2x2 12V power connector

What does "Do not insert the power supply cables into pins under the protective covers" mean? I'm not sure of this.


Do you have the cpu fan plugged into the fan header?

Here is the best way to test a system, if this doesn't work, I would try a 8pin power supply or suspect that a cpu or motherboard is faulty.

In order to trouble shoot this issue, let's try a bench test:
  • Remove the motherboard from the case and place it on a piece of cardboard
  • Install only the CPU with heatsink and fan (remember to use thermal paste and plug in the fan)
  • Install only 1 stick of ram in dimm 1 (consult your motherboard manual for which slot is to be used)
  • Hook up the Power Supply (there should be a 20 or 24pin connector, and a 4 or 8pin connector)
  • Use onboard video, (if not available, use a video card)
  • Use any momentary case switch, or have your case close enough to install it's case switch
  • Make sure there is a case speaker connected, many modern motherboards have a onboard speaker
  • Connect a ps2 mouse and keyboard along with the monitor (if all you have is USB, that's ok)
  • Power the system on
  • Can you get to the BIOS? (Consult motherboard manual on how to enter the BIOS)
DO NOT hook up the hard drive, CD/DVD, case fans, lights, or anything else not mentioned above.

If the system does not power on, replace the 1 stick of RAM with the other stick. Are you getting any kind of beep codes? Do you get any video? Do the fans remain on, but no video?

Hope that helps. :) Let me know how things go.

Edited by Ferrari, 04 April 2010 - 08:02 PM.

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#3
Dr. Vick

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Solved.

It was an incompatible power supply. Though the motherboard manual doesn't mention it, it seems a PSU with an 8-pin connector was required. I took the system to a PC repair shop and they said they got it working after hooking up a new PSU.
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#4
Ferrari

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Awesome. :)
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