# Motherboard power LED is on, but PC won't start



## Hazmat (Dec 30, 2008)

I received a new graphics card in the mail yesterday, and when I installed it the computer wouldn't start. Thinking it was a faulty card, I switched back to my old card, and the computer still wouldn't start, no fans spinning or boot noises or post. This didn't make sense because everything is exactly the same as my setup that was running earlier in the day.

I searched around online and began assuming that my power supply was fried, but I tried the paperclip test and the fan on the PSU does spin, but when connected to my motherboard nothing happens.

Things I have tried:
1. Removing and reseating all wires and components.
2. Paper clip test on PSU.
3. Different PSU cables.
4. Different wall outlets.
5. Making sure the power button wire is properly connected.

Things that I suspect are causing the problem:
1. Fried PSU.
2. Fried Mobo.
3. Fried/broken HDD? I did have to move the HDD while installing my new card and could have possibly bumped it too hard or something. I've also seen other PCs not turn on when a HDD is not connected properly, even though I'm sure mine is. Does it matter where/how (silver side up or down?) the HDD is mounted?


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## loda117 (Aug 6, 2010)

HDD does not have anything to do with your motherboard not turning on 

I would check the Power switch connection from the front of the case to the motherboard and that it is connected the right way 
Look on the board for any capacitors bent or damaged (during replacement of cards it might have happened) 
also link your PSU model and specs


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## Johnny1982 (Oct 15, 2010)

Make/model/wattage of PSU and what graphics cards did you use.


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## greenbrucelee (Apr 24, 2007)

Please post your full computer specifications inlcuding make and model of power supply.
If your system is oem i.e one you have bought from a shop such as a dell, hp or compaq please post the model number.
Posting your specs can help us to help you better.


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## Hazmat (Dec 30, 2008)

Mobo: MSI 785GT-E63
PSU: Thermaltake Black Widow TR2 RX-850 AP
CPU: AMD Phenom II X4 940 Black Edition
RAM: 8GB G-Skill 1066 Mhz
GPU: MSI R5770 Hawk/MSI R6870 Hawk

I am positive the power switch wires are connected properly, and I've even tried the power button on the mobo, which also does not start the computer.

I do not see any bent capacitors anywhere on the mobo, but the pins for one of the case fans are bent. I don't know when this happened, but I've tried powering on the PC with and without the case fan plugged in.


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## Johnny1982 (Oct 15, 2010)

I read now on Bestbuy someone that purchased that PSU saying that it has the POWER but not the CURRENT to get the PC started. I would suggest trying a different PSU to rule this out. I don't know Thermaltake PSU's and which ones are good or bad, but that does not sound good to me. Could also just be an isolated issue.:4-dontkno


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## Hazmat (Dec 30, 2008)

I've been using this PSU for over a year with no problems, until now that is. I just want to be sure before I go out and buy another PSU.


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## Tyree (May 10, 2009)

The TR2 RX-850 is a very poor quality HEC made PSU making it a good suspect. 
Using the old GPU, clear the CMOS and boot the PC.
I assume the 5770 is the older GPU and the 6870 is the replacement?


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## greenbrucelee (Apr 24, 2007)

The only thermaltake power supplies we would recommend are the tough power series.


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## Hazmat (Dec 30, 2008)

Tyree said:


> The TR2 RX-850 is a very poor quality HEC made PSU making it a good suspect.
> Using the old GPU, clear the CMOS and boot the PC.
> I assume the 5770 is the older GPU and the 6870 is the replacement?


Yes, the 5770 is the older GPU. And I've already cleared the CMOS, hasn't helped.


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## Tyree (May 10, 2009)

I would do a bench test.

Remove EVERYTHING from the case.
Set the motherboard on a non conductive surface. The motherboard box is perfect for this. DO NOT PLACE THE MOTHERBOARD ON THE STATIC BAG! It can actually conduct electricity! 
Install the CPU and heat sink. 
Install 1 stick of RAM.
Install the video card and attach the power supply connection(s) to the card if your card needs it.
Connect the monitor to the video card.
Connect the power supply to the motherboard with both the 24pin main ATX Power connection and the separate 4 or 8 pin power connection.
Connect power to the power supply.
Do NOT connect ANYTHING else. Make sure you have the power connector on the CPU fan connected.
Use a small screwdriver to momentarily short the power switch connector on the motherboard. Consult your motherboard manual to find which two pins connect to your case's power switch. Then touch both pins with a screwdriver to complete the circuit and boot the system.

If all is well, it should power up and you should get a display. Then assemble the parts into the case and try again. If the system now fails to boot, you have a short in the case and need to recheck your motherboard standoffs.

If the system does not boot after this process, then you most likely have a faulty component. You'll need to swap parts, start with the power supply, until you determine what is defective


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## Hazmat (Dec 30, 2008)

Tyree said:


> I would do a bench test.
> 
> Remove EVERYTHING from the case.
> Set the motherboard on a non conductive surface. The motherboard box is perfect for this. DO NOT PLACE THE MOTHERBOARD ON THE STATIC BAG! It can actually conduct electricity!
> ...


I tried this and got no results. Unfortunately I don't have a spare PSU lying about, so I'll have to go buy one. Hope that solves the problem.


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## Tyree (May 10, 2009)

Best of luck and please let us know how it turns out.


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## Hazmat (Dec 30, 2008)

I just installed the new PSU and had no luck, until I figured out that removing my network card allows the PC to power up. But now once it powers up, it doesn't post.

All LEDs, fans, and drives are working. Hard drive spins and boots but no monitor signal and no post beeps.

Yes the speaker is connected properly.


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## Tyree (May 10, 2009)

What GPU are you using and what is the Brand & Model of the replacement PSU?


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## Hazmat (Dec 30, 2008)

MSI R5770 and R6870 for the GPU, the PSU is the exact same except a newer version (2.3 instead of 2.2) as it's the only one that I could get on short notice.

Based on another thread (one which you replied to, Tyree, and told me to start my own thread), I'm assuming my mobo is ****** as it didn't give me an error beep when removing all of my RAM.


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## Johnny1982 (Oct 15, 2010)

Hazmat said:


> MSI R5770 and R6870 for the GPU, the PSU is the exact same except a newer version (2.3 instead of 2.2) as it's the only one that I could get on short notice.
> 
> Based on another thread (one which you replied to, Tyree, and told me to start my own thread), I'm assuming my mobo is ****** as it didn't give me an error beep when removing all of my RAM.


As Tyree pointed out, that Thermaltake PSU is not good and you go out and buy the same. Where's the sense in that. Doesn't mean because it's new it will definitely work.


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## Hazmat (Dec 30, 2008)

Johnny1982 said:


> As Tyree pointed out, that Thermaltake PSU is not good and you go out and buy the same. Where's the sense in that. Doesn't mean because it's new it will definitely work.


It's the only thing I could get the same day without paying a ridiculous price.


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## Johnny1982 (Oct 15, 2010)

Hazmat said:


> It's the only thing I could get the same day without paying a ridiculous price.


Ridiculous price probably refers to the PSU you should get. A decent brand name PSU.


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