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Computer won't boot after power outage, is it the Motherboard or PSU?

I finally came to a final decision about the problem I'm having with my computer. The problem is that my computer is not POSTING after a power outage, and I believe that it is either the PSU or motherboard. All the other hardware (ram, graphics card, etc) is working fine. But I do not know which one is deffected, is it the motherboard or psu, so I need some help to choose which one to replace. Here are some problems that might help you choose which is the problem.

Motherboard Signs that it is broken:

1. The front fan is not working, it is connected to the motherboard, but all the other fan is working fine. It is connected to a port near the bios chip, so maybe there is something wrong with the circuit near there that is causing the computer to not post.

2. The motherboard seems to be powered throughout, and everyhting else aside from that one fan is not turned on.

Motherboard signs that it is not broken:

1. For some reason, occasionally, my computer would work. The one fan

Update:

that's broken would turn on. The computer would post to and the blue led infront would turn on. The computer worked for the whole day with no problem, but when I turned it off for the night, then turned it back on in the morning it wouldn't post again!

Update 2:

The CPU fan is working. I tried to reset the cmos, but no display and post. I also tried reconnecting everyhting and putting it back.

6 Answers

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  • 1 decade ago
    Favorite Answer

    Most motherboards (to my knowledge) have a light somewhere on it. You motherboard could be burnt out. If it is, the light won't be on.

    I'm not a computer techy though, I only know this because I had that problem with my motherboard a while back.

  • 1 decade ago

    There could be a number of issues, here, but we'll deal with the most obvious. The last post was right, the "link" light should come on the moment you provide power (check and make sure that the power supply is switched on, in the back, and that the Voltage setting is set for 120VAC and not Int'l.).

    First thing to check, make sure ALL cables and connections are secure. Nothing confuses a MoBo more than having a "shorted" connection somewhere.

    Second, reset the CMOS. This is different for every manufacturer but the most common way is to find a jumper (sometimes labelled JP5) near the battery and change it to the reset (it's normally connected to two of three pins, switch it to the other side with the center one always being used). Then power the system up and it will either do absolutely nothing or the fans will come on for five seconds and then shut off on their own. Switch the jumper back and turn the system on again. Hit the <Del> key to bring up the BIOS (binary operating system) for the motherboard itself. You'll have to set the date/time and check your other settings.

    Third, try unhooking all peripheral devices (CD, floppy, etc.) and boot it up with just the motherboard, video and input devices (mouse and keyboard) and then reattach them, one at a time.

    My guess is, just resetting the CMOS will do the trick. I've worked on thousands of computers and that works nine out of ten times.

    Good luck and please let us know.

  • weiner
    Lv 4
    5 years ago

    There could be a number of subjects, right here, yet we will manage the main glaring. The final post replaced into appropriate, the "hyperlink" gentle ought to come on the 2nd you supply potential (examine and make helpful that the potential supply is switched on, interior the returned, and that the Voltage putting is set for 120VAC and not Int'l.). first ingredient to envision, make helpful ALL cables and connections are preserve. not something confuses a MoBo extra beneficial than having a "shorted" connection someplace. 2nd, reset the CMOS. this is diverse for each producer however the main ordinary way is to come across a jumper (each so often labelled JP5) close to the battery and alter it to the reset (this is regularly linked to 2 of three pins, swap it to the different area with the middle one continuously getting used). Then potential the equipment up and it will the two do truthfully not something or the followers will come on for 5 seconds and then close off on their very own. swap the jumper returned and turn the equipment on returned. Hit the Del key to improve the BIOS (binary working equipment) for the motherboard itself. you will ought to set the date/time and examine your different settings. third, attempt unhooking all peripheral units (CD, floppy, and so on.) and boot it up with merely the motherboard, video and enter units (mouse and keyboard) and then reattach them, one after the different. My guess is, merely resetting the CMOS will do the trick. i've got worked on 1000's of computers and that works 9 out of ten circumstances. stable success and please let us know.

  • Anonymous
    1 decade ago

    I believe that the problem is that the CPU fan on the motherboard is not coming on every time you start up the PC. If the fan does not come on, the MB is most likely not letting the PC start up, because if it did without the CPU fan running, the CPU would burn up.... Replace the CPU fan, it should be only $10 to $20. See if that does it.

    Source(s): Me
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  • 1 decade ago

    Given that your computer is sometimes working intermittently / partially, it may be that nothing is burnt out. Can you check by going into BIOS settings at startup, or aren't you even seeing that?

    Has something come loose? E.g. if the motherboard can't detect the CPU fan working it will refuse to boot, to prevent the CPU over-heating.

  • 1 decade ago

    Usualy in a power surge, it is the PSU that takes the damage. It is design to take the main force of the surge and protect the rest of the board. Most people would rather replace a $40 PSU then a $400 board and processor. I would change the PSU first.

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