Custom PC Won't Turn On


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  1. mrhomiec

    mrhomiec Well-Known Member

    so my friend asked me for assistance today.

    in short- the computer won't turn on.

    in long- on Sunday, she was on her computer, then a burning smell started, but it didn't smell like it originated from the computer. upon taking about 20-30 minutes of trying to track down the burning smell around the house, couldn't locate the source of smell. come back to the computer, it was turned off automatically. (i'm assuming the computer shut itself off due to a high CPU temp?)

    now, when you try to turn it, a light flashes once on the case, the case fan and CPU fan twitch, and nothing else happens.


    here's what i've tried:

    * unplugged everything from the motherboard. then plug it all back in.

    * unplugged the cable from power supply to wall, and back in.

    * flipped the power supply switch on and off.

    * removed video card, tried to boot- nothing.

    * removed RAM, tried to boot- nothing.

    * removed CPU fan, the AMD processor looks fine. could use a new heat sink and fan.

    * removed CMOS battery, inserted backwards, removed again, and then inserted correctly.


    computer information:

    * board - ASUS M4A78T-E ASUS - Motherboards- ASUS M4A78T-E

    * processor - AMD AM3 socket

    * RAM - 4GB DDR3 (2x2GB)

    * video card - ATI Radeon


    right now, i'm thinking to test the power supply. since even the case fan won't start up?

    if that doesn't work. i'm thinking it's either the motherboard or processor?

    let me know what you think, thanks!

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  2. SirSpace

    SirSpace Well-Known Member

    What you got right there is a burnt CPU almost positive best way to find out only put power supply to motherboard HD just the basics. Then do this just put in ram and CPU not the HD if kt don't boot up then its the CPU. It can't be the power cause you said the fans twitch and a light comes on. Try swapping out the CPU with another one if available. But sounds like she burnt her CPU. It can't be the ram cause u said he has 4 gigs so prob she has 2 2gig stick or is it one? But u said case fans don't come up. Try just putting power to motherboard nothing else see if it will boot up if not then yeah its the power.
    argedion likes this.
  3. mrhomiec

    mrhomiec Well-Known Member

    yea- i edited the post for 2 sticks of RAM.

    i have a power supply checking thing, so i'll try that out first.

    thanks.
  4. Speed Daemon

    Speed Daemon Disabled

    The last PSU tester I bought has a LCD display that shows the voltage of the various power busses. If yours doesn't, you can use a multimeter to check the voltage. Just make sure the PSU is under load!

    Although I have seen one (and only one) PSU die horribly in a cloud of smoke, the more likely point of failure is something on the motherboard. This could be things that you can replace, like the CPU and/or RAM. It could also be something like the on-board CPU power supply, the one that steps down higher voltages from the main power supply to the precise voltage requirements of your CPU.

    If you have a spare CPU and RAM, you can swap in "known good" parts, or if you have another motherboard you can test each removable part separately. If not, a big box store technician can do it for you.

    What was the physical condition of the PC as you found it? Were any of the fans (or fan shrouds) clogged with dust bunnies or anything else that could have stopped a fan from spinning? Do all of the fans turn smoothly and easily by hand? If, for example, the CPU fan is clogged and/or seized, the CPU is likely to be overheated. You can't tell just by looking at the part; it must be tested to know for sure. But finding a CPU or GPU fan that might not have been working can help track down the source of the problem.
  5. mrhomiec

    mrhomiec Well-Known Member

    I couldn't find my PSU tester. So I'll be trying out other things later today.

    All the fans turned very easily. The only noticeable dust was on the case power supply fan. Her case has the power supply housed on the bottom, and there's dust build up on the bottom of the case. I couldn't look at this very well at the time, I was unable to lay it on the side to see the bottom. From the case standing though, I could see dust under there.

    I thought I tried to boot it without the CPU plugged in. But now I'm not sure. I know I at least removed it to look at it.

    She did mention that her CPU fan used to make noises a few months back. Even without anything touching the fan, like the cable or something.

    And unfortunately I do not have any working spare parts to put in and test.
  6. SirSpace

    SirSpace Well-Known Member

    If u did take the CPU out and turned on computer it wouldn't do anything. It will start but it won't tell you if the CPU is fried. Only way to figure that out is swapping it with another. As for the dust issue unless the dust is on the grill protecting the fan blades where it blows the hot air out of the power supply I can't see it causing a problem like this. I'm still going with the CPU or power supply how many watts is it.
  7. mrhomiec

    mrhomiec Well-Known Member

    it's a 700-watt OCZ PSU.

    if i could at least just get to the BIOS. or even a boot screen, that'll help a lot too. will be trying all these suggestions later today.
  8. IOWA

    IOWA Mr. Logic Pants Moderator

    Pull out the Mobo and check for burnt capacitors or circuits, any kind of burnt components. Since it's not even getting to POST, it's most likely MOBO or CPU. Right now it's most guess and check though. You need good RAM, CPU, and MOBO to pass post. (And of course a PSU)
  9. dmodert66

    dmodert66 Well-Known Member

    I work for a computer component manufacturer. Likely, your PSU caused the acidic smell (if that is a correct description of the smell). The PSU could have taken out the mobo. Remember, if a component in the PSU burned, it may still turn on, but not properly power everything. That said, I would bet both the PSU and the Mobo are toast. Newer CPUs rarely die from a power supply dying out, but that is certainly possible as well. Your best bet is to do as IOWA says, test another PSU first. Another faulty component won't damage another PSU, so that should be your starting place.
  10. Speed Daemon

    Speed Daemon Disabled

    With the PSU on the bottom, there's a greater chance of dust and other stuff getting into the PSU and causing it to overheat. In your case I'd suspect the PSU more.

    It's not going to do much without a working CPU and working RAM, so if it just sits there when you turn it on, it's a good sign that one or the other (or both) has/have failed.

    I've had noisy fans bother me from time to time. I usually replace them before they can fail. Once I was at a client site and noticed that their only file/print server was making fan noises. The company's tech said it's no big deal but I insisted on taking a look. When we opened the case, the fan burst into flames. I had saved the CPU from heat damage just in time! A new CPU fan from an unused heatsink got the server back online, and not a bit of data was lost. That's a one-in-a-million catch though.

    That's the problem that most people have. The failed server I mentioned above is still running with more RAM (uses SIMMs!) and a new hardware-based RAID array to replace the pair of software mirrored half-height SCSI drives that I found in it. That's part of my business, to be able to deal with old, out of production hardware and software. I keep stockpiles of vintage parts for that purpose. You might be better off turning it over to the Geek Squad or some other computer tech service if you don't have extra parts to swap in.
  11. SirSpace

    SirSpace Well-Known Member

    If I were you take a psu out of any computer dell Acer w.e throw it n regardless of watts I'd deff shoot for at least 500 this way you can tell if its psu or mobo right away. So if you can get that your problems would start to disappear
  12. mrhomiec

    mrhomiec Well-Known Member

    [UPDATE]

    i found my PSU checker. and the power supply is still kicking.

    and since i don't have anything to test to see if the motherboard or CPU is fried, it seems like the only next step is buying new ones. =P

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