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Computer won't turn on. Power supply is okay. Is the motherboard bad?

I'm going through the steps in this tutorial (http://pcsupport.about.com/od/findbysymptom/ht/nopowertopc.htm) to deal with a system that will not turn on. I got past the power supply, where I managed to test all of the pins for the proper levels. I didn't check the power button because I'm afraid of hitting the wrong pins and damaging my board, although I will if I have to.

My next step was to check my motherboard by buying a POST card, but I'm hesitant if there is another way or if buying one will put me out more than it's worth. Is there anything else I can check? Is buying a POST card worth it for fixing one system?

BTW the board is an Asus M2N MX SE.
35 answers Last reply
More about computer turn power supply okay motherboard
  1. Unplug everything except the CPU/HSF, PSU, 1 stick of RAM, and the front panel power switch. Connect your monitor to your onboard video. Everything else can be disconnected.

    Try powering on. Do you hear any beeps?
  2. When I flick the PSU switch, the green light on the motherboard turns on. When I hit the front panel power switch, the CPU fan starts to spin but then stops. The PSU fan never seems to kick on, although when I was jumping the pin, it seemed okay to me.
  3. I don’t think that a Post card will give you any meaningful information, so I would not buy one just to test this system, the money would be much better spent on a new power supply as this is probably the fault and if it isn’t then you have a spare for when it does go faulty in a few years time.
  4. pjmelect said:
    I don’t think that a Post card will give you any meaningful information, so I would not buy one just to test this system, the money would be much better spent on a new power supply as this is probably the fault and if it isn’t then you have a spare for when it does go faulty in a few years time.


    Well, when I tested the PSU, I think I followed the tutorial fairly well. All of the pins are within range. But I'm new to this so I might have done something wrong.. Are there more thorough tests one can do?
  5. Try unplugging the monitor in addition to what is already unplugged.
  6. aford10 said:
    Try unplugging the monitor in addition to what is already unplugged.


    Nah, still the same as before..
  7. If you can borrow someone's PSU, that'd be a good next step.
  8. aford10 said:
    If you can borrow someone's PSU, that'd be a good next step.


    Yeah, that's probably not going to happen. I'm very much a loner :/ I'm debating if buying a new PSU is worth it.. And what to do if that doesn't hep.. It would be the second one I bought today!
  9. What model is the old and new PSU? What kind of video card?

    Make sure the 4/8 pin CPU power is plugged in.

    Do you have a motherboard speaker?

    Randomly buying parts isn't the best way to tackle this. There are some ways to help narrow it down.
  10. If you want to test if the motherboard is working. ( you need a motherboard speaker) Take out all of your ram then turn it on if you hear a beep then your motherboard is ok if you don't then your motherboard has broken.
    This worked for me and I went out and got a new motherboard then it was fine.
    hope this helps
    from
    Jordan
  11. I am reading this, and I hear you say that you do not want to try to start the board by shorting across the 2 power pins. However, you state that you are certain the power supply is not bad, because you have tested each of the power supply leads with a tester. Your statements lead me to believe that your assessment of your PSU may not be conclusive.

    A motherboard speaker, so you can listen to beep codes, is a must for troubleshooting these things. You can buy one for like $5.
  12. aford10 said:
    What model is the old and new PSU? What kind of video card?

    Make sure the 4/8 pin CPU power is plugged in.

    Do you have a motherboard speaker?

    Randomly buying parts isn't the best way to tackle this. There are some ways to help narrow it down.


    Sorry for the confusion, yesterday I ordered a new PSU for another system, not this one..

    The videocard is a GeForce 7200 GS. The 4 pin CPU cable is plugged in. I checked with the multimeter yesterday and it seemed okay. A far as a mother board speaker, I think I've heard it beep before, but I can't quite remember.
  13. Look near your front panel wiring on the motherboard. The motherboard speaker will look like this
    http://img.auctiva.com/imgdata/1/3/1/4/5/3/2/webimg/315853401_o.jpg

    If you don't see something that looks like that, you may want to get one.
  14. aford10 said:
    Look near your front panel wiring on the motherboard. The motherboard speaker will look like this
    http://img.auctiva.com/imgdata/1/3/1/4/5/3/2/webimg/315853401_o.jpg

    If you don't see something that looks like that, you may want to get one.


    Nah, I don't have one.. I'll probably have to go downtown and pick one up today.
  15. jitpublisher said:
    I am reading this, and I hear you say that you do not want to try to start the board by shorting across the 2 power pins. However, you state that you are certain the power supply is not bad, because you have tested each of the power supply leads with a tester. Your statements lead me to believe that your assessment of your PSU may not be conclusive.

    A motherboard speaker, so you can listen to beep codes, is a must for troubleshooting these things. You can buy one for like $5.


    I followed this tutorial (http://pcsupport.about.com/od/toolsofthetrade/ht/power-supply-test-multimeter.htm). Checked the motherboard and CPU pins. I don't have a hard drive connected to this machine so there were no others to check. But like I said I'm new to this so I might have made a mistake somewhere, so might try it again, going through it more carefully.
  16. Quote:
    Nah, I don't have one.. I'll probably have to go downtown and pick one up today.


    Looks like none of the shops downtown have any. I ordered one online, so I won't be able to respond until it shows up in the mail. For now, thanks for all your help aford10.
  17. No problem. Just let us know when it shows up.
  18. Here is a simple thing that might help. I thought I had a motherboard issue similar to yours, no signs of life except fans. Change the clock battery. I did this and my computer started right up. It's funny how no one seems to come up with that answer. ASUS was ready to RMA mine, but I found my own solution. Hope it's not too late to help :bounce: .
  19. I got my motherboard speaker in the mail on Friday and decided I'd try it out right now. I downloaded the manual for the motherboard and I think I have the right pins.. I turned it on and.. nothing. No beeps. I pulled it out and flipped it around and still nothing. I'm going to look up the clock battery and give that a shot.
  20. did changing the clock battery work?

    Have similar problem,PSU tests ok when isolated,but PC wont turn on when connected to mobo and peripherals


    robinhoode said:
    I got my motherboard speaker in the mail on Friday and decided I'd try it out right now. I downloaded the manual for the motherboard and I think I have the right pins.. I turned it on and.. nothing. No beeps. I pulled it out and flipped it around and still nothing. I'm going to look up the clock battery and give that a shot.
  21. I had a similar problem but i had to take out the graphics card and run start-up on internal motherboard display. Try that
  22. kastor900 said:
    I had a similar problem but i had to take out the graphics card and run start-up on internal motherboard display. Try that



    @kastor900

    Where exactly do you think the internal MoBo display wille be situated on a Asus m2n -sli de luxe.

    I personally do not think there is one on this MoBo, so what do you suggest instead?
  23. Had the exact same problem, press the power button, can see the cpu fan spin and then nothing. Swapped out PSU, RAM, CPU, and removed video card. Finally, I change the CMOS battery and that worked! Glad it wasn't the motherboard and I had lots of spare hardware to swap in! :)
  24. robinhoode said:
    I'm going through the steps in this tutorial (http://pcsupport.about.com/od/findbysymptom/ht/nopowertopc.htm) to deal with a system that will not turn on. I got past the power supply, where I managed to test all of the pins for the proper levels. I didn't check the power button because I'm afraid of hitting the wrong pins and damaging my board, although I will if I have to.

    My next step was to check my motherboard by buying a POST card, but I'm hesitant if there is another way or if buying one will put me out more than it's worth. Is there anything else I can check? Is buying a POST card worth it for fixing one system?

    BTW the board is an Asus M2N MX SE.


    It could be that the heatsink fan is not properly seated on the CPU or that there is not enough thermal paste (also, too much thermal paste will not allow heat transfer through to the heatsink).

    If the PSU is less then 300 watts then that could be a problem.
  25. I had similar (not exactly same) but similar, and I solved this way:

    MY COMPUTER WAS NOT TURN IT ON- AT ALL

    - I took cables away (every cable) from the mobo
    - After that -no cables connected except the 24 pin- I connected the power supply and turn it on and it turned on!
    - I realize then that I have a short circuit problem-
    - I put back each of the cables- one by one, and at same time turning on the PC to see where the problem was.
    - When it was the time to connect one of the cables to the mobo I turn the PC on but it did not, so I realize that it was the problem- (one of the cables had short circuit)
    - That small cable was the big problem, and was only a led cable -not so important for the PC to work-
    - So I disconnected that cable and not used anymore- and my PC is fine now.

    SO THE LESSON is: when you install cables in the MOBO I believe you have to be very careful- cause can cause a short circuit. And in order to diagnose properly you have to do it ONE BY ONE step.
  26. there are 2 posibilities, faulty ram on try removing the bios battery
  27. On my new build my problem was my 600 watt power supply was not enough to power my new motherboard... Make sure your power supply is good enough.
  28. I have a similar issue but none of these results worked so far.. What happened was the breaker on the house popped and the computer shut off and when we reset the breaker the computer wouldn't turn on, so i took out the PSU and tested it and it turns out it was fried so i got another spare PSU i had from a older version of the same computer just has a little more amps but it will not start when i hook it up to my mobo.. i did a short to manually start it with everything but the mobo and it seems to turn on fine but as soon as i try starting up the computer it will not turn on.. Any help?
  29. Hey Robinhoode,
    After going through your problem i suggest disconnect the front panel pins,then again connect them except the power leds (both positive and negative) and the power switch pin (so i mean just connect HDD led and reset switch).
    Now u wont be able to switch it through power on button but use a screwdriver and touch the 3rd and 4th pin i.e power switch pins (which should switch on the CPU )
    Let me know if it helps
  30. Televirtual said:
    I had similar (not exactly same) but similar, and I solved this way:

    MY COMPUTER WAS NOT TURN IT ON- AT ALL

    - I took cables away (every cable) from the mobo
    - After that -no cables connected except the 24 pin- I connected the power supply and turn it on and it turned on!
    - I realize then that I have a short circuit problem-
    - I put back each of the cables- one by one, and at same time turning on the PC to see where the problem was.
    - When it was the time to connect one of the cables to the mobo I turn the PC on but it did not, so I realize that it was the problem- (one of the cables had short circuit)
    - That small cable was the big problem, and was only a led cable -not so important for the PC to work-
    - So I disconnected that cable and not used anymore- and my PC is fine now.

    SO THE LESSON is: when you install cables in the MOBO I believe you have to be very careful- cause can cause a short circuit. And in order to diagnose properly you have to do it ONE BY ONE step.
  31. This advice of removing all cables except the 24 pin on the MOBO helped us to see that ours was still functioning properly. Then when we added them back one by one we found a backwards four pin, corrected it and viola! Computer working. Thank you thank you....can't thank you enough.
  32. hi guys i have very old computer magic station gv20 it has a old mb and old psu.i have used it for 3 years but no problem with my computer.
    one day my computer won't turn on i remove the casing and try to troubleshoot the problem,Then i saw a green light in the mother board, that means
    power is coming through the psu to mb but doesn't come to the power button.i looked the connection wire between mb and the power button
    the wire was LOOSED.you only have to do is fix the wire tight thats all no need replace the psu or the mother board. sorry for bad English.
  33. I also have a similar problems as the OP. I checked some the pins on the PSU and got good readings for the 24 pin and the 8 pin needed for the mobo and the PCI ones that I'm using for the GPU. My problem is when I press the power button nothing happens. I plug in the power cable, flipped the switch on the psu to turn on and can see the green light on mobo turn on, press the power button on case and nothing. I took out all the parts to cleaned (problem occurred before I did this) thinking it's because it's dirty. Took out everything including the cpu. Put everything I needed to turn on (pretty much the power cables to mobo only the 24 pin and 8 pin) and nothing. Changed the cmos battery like someone here mentioned and nothing. I'm thinking my mobo is fried. When i unplugged the power cable to one of my SSD the part on top of the pins had broken off so you just see the pins. Maybe that fried the mobo.
  34. ChecK super I/O controller chip and check 24 pins ATX power connector also check 5VSB supply.
  35. Thank you, my pc was fix by changing the CMOS battery.
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