Shorted out my PC. How do I know which components were damaged?

sickleandsuckle · Sep 19, 2016

Hello everyone,

I made a horrible, horrible mistake and was doing some modification to my PC interior WHILE the computer was running. I installed a case light for my PC, and was trying to move it around while the lights (and thus the PC) were on. It was connected to a 4-pin connected directly to the PSU. While trying to move the dangling strip around, it touched the PCB connected to the power button, and the whole setup shutdown, with the sound of a switch (probably from the PSU).

This is the lighting strip in question: https://www.amazon.com/gp/product/B00JR3UXXK/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

This is the PSU in question:
http://www.newegg.com/Product/Product.aspx?item=N82E16817438053

Now the PC will not turn on, under any circumstance.

I talked to a friend and he said that it should just be the PSU that is broken but I'm not completely sure. Could the motherboard been affected by this, and thus the CPU and GPU as well?

I am currently awaiting a PSU tester (I lost the one that was provided with the PSU) to see if it is one of the components that broke, or if it is the only one that did.

amtseung · Sep 19, 2016

If you shorted the PCB for the power button, that's essentially the same as pressing the power button. You could try unplugging the power button from the motherboard and bridging the two pins with a screwdriver. If it still doesn't boot, then we know you broke more than your power supply. That switching sounds is, in all likelyhood, the short-circuit/overcurrent protection relay within the power supply, tripped when you shorted the LED strip, not the power button PCB. Does the PC not boot even with the LED strip disconnected?

I would also try yanking out the PSU and looking up the paperclip test method. Essentially, it's bridging the green wire on the 24pin loom to one of the black ones, which gives it the signal to power on. Unless it's one of them nicely painted ones, then you gotta do some counting.

If the power supply turns on, then you can use the PSU tester to see if it's getting proper voltages at all. See if you can borrow someone else's power supply to test your remaining componentry. Worst case scenario, find a local electronics store that sells PC parts and things and has a return policy, so you can buy stuff to test with and return it when you're done, assuming you don't damage anything, and that they have a super lax return policy like Fry's. I suspect you may have other dead components in there as well, but let's move one step at a time.

Your PSU came with a tester? Lucky.

sickleandsuckle · Sep 19, 2016

No, I haven't tried doing that screwdriver method. Are there any significant risks to this? I don't want to (further) damage the components. The PC does not boot even with the LED strip disconnected.

The PSU tester essentially does that, it's not a voltage reader or anything, just a jumper that triggers the PSU to power on. I will watch to see if the fan moves or not, and if it doesn't, then I'll know it's among the parts that are dead.

I have already ordered a new PSU (nearly the exact same model) in the case that the PSU is dead, so I'll have one at the ready.

---

Here's an odd thing though. My PC is connected to a surge protector which is connected to a strange outlet, in that its internal circuit breaker (the outlet's) will trip if I turn on the lights WITH my PC plugged in. It does this even if my PC is the only thing plugged in, and when the PC is off. I've accidentally turned off my computer a few times doing that, though not too recently. It has never tripped while operating, unless the lights are off and I turn the back on.

When I plug in just the power supply, no connections, the circuit does not trip when the lights turn on. However, if I plug in the 24 pin for the motherboard into this power supply, the circuit trips. I feel like if the PSU was dead it would not do this...but I could be wrong.

I plan to not use that outlet anymore anyway; I'm gonna get an extension cord for use with another outlet.

amtseung · Sep 20, 2016

The screwdriver/paperclip/conductive metal object connects the two pins, doing exactly what a power button does. It won't harm anything unless you press too hard and bend something.

Most of the ebay PSU testers I see read basic voltages from each of the non-ground wires, and do something along the lines of light up green within a certain range of voltages, and not light up otherwise. You can't exactly jumper a power supply with one of those block-shaped jumpers and have it still plugged into the motherboard, and you can't exactly test boot a PC without that 24pin loom in the motherboard. Unless it's a strange block-shaped jumper I've never seen before.

When someone says a PSU is "dead", it doesn't mean that there's absolutely no power going through it at all. A dead PSU can still provide partial amperage at the correct voltage, but under a full load, like the initial surge on boot where it pulls 100% power as part of the post process, it will fail to deliver. A dead PSU can even provide full amperage at the correct voltage, just a really unstable power delivery where none of the voltages or amperages are steady and consistent. These are the worst kinds of dead PSU's, because to the average home user, they look/sound/feel/perform like normal, until they fry another full complement of hardware, and then think to themselves, "gotta be something else", and the real problem is never fixed.

Your outlet is probably telling you that you're overloading that particular wall circuit. What you could probably do is use that outlet to power nothing other than the PC, and use surge protected extensions to power your monitor and other things from another outlet. I'm particularly lucky in my bedroom where each of my power hungry desktops get their own individual outlet, and the monitor, speakers, laptop charging, desk fan, etc. get yet another outlet with a power strip on it. I have everything surge protected except my lamp, which has its own outlet, all on its own. And I still have a 5th power outlet with nothing plugged into it.

sickleandsuckle · Sep 20, 2016

Does that mean that the block jumper might give a false positive, and that I should get something like this? (I had already ordered it, so if that is true I will have a better tester at the ready).

https://www.amazon.com/gp/product/B005CTCD6S/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

That doesn't sound good, the fact that dead PSUs can still deliver power. You could use the same defective PSU and burn out so many electronics!

I have already bought an extension cord to stop using that outlet (I shouldn't use a kitchen outlet for a PC, anyway). Hopefully that should help.

---

My tester and new PSU come today, so I will try using that and test the old PSU very soon. I'll let you know how it goes.

sickleandsuckle · Sep 22, 2016

So I got the PSU tester to see if my PSU might be a damaged component. And it turns out it still works...but when plugged into the PC, it doesn't:

I know, like you said, that dead PSUs do not mean that no electricity follows through them. The -5 V LED is not lighting up (but apparentely manufacturers don't have PSUs deliver that anymore). Like you said though, the PSU may be able to deliver power but it may not be able to get 100% like as needed to start up the computer.

I did try the screwdriver method but to no avail. Thing is, do you need to remove ALL the case wires connected to the PC? I only disconnected the ones that connect to the power button pins.

amtseung · Sep 22, 2016

If the screwdriver method isn't working, then your motherboard is fried. What you're doing with your screwdriver is turning it into the power button, so if it won't start up and/or stay on, then it's your motherboard that's dead, not your power supply.

I did something similar to my system about a month ago, fried both motherboard and CPU. I extensively tested my own PSU with my friends' digital multimeter and oscilloscope, and it was hunky dory, but the motherboard refused to function with known working CPU's in it, and my CPU refused to work in known working motherboards.

Now it's time to figure out what other components in your system are dead. Do you have a spare/ancient/back up system you can swap parts into and test?

sickleandsuckle · Sep 22, 2016

Unfortunately I don't. This was my first build, and was working for 1 month before I shorted it out.

Though since a new PSU is coming in the mail I might as well test that too. If that doesn't work....

Well I guess it's time for me to drain my debit account for another motherboard. And potentially GPU and CPU...

...maybe it's a good idea to quit gaming as a hobby.

mjslakeridge · Sep 22, 2016

...maybe it's a good idea to quit gaming as a hobby.

It wasn't gaming that is the problem, it was messing around inside the case with the computer powered up. But you already know that.

Hopefully it is just the motherboard that got fried. I am just speculating, but I think that is likely.

Good Luck!

sickleandsuckle · Sep 22, 2016

Thankfully the motherboard was only $90, which was around the price of the PSU. I'll just go refund the PSU I had just bought.

Assuming that the other components weren't harmed.

I'll see how installation goes this weekend.

Just out of curiosity,
If a short circuit goes through the power-button/power-LED assembly, what are the chances that it shorted out the CPU and GPU as well? Or the RAM? Or even the hard drives?

Or is there no real telling?

bwinzey · Sep 22, 2016

sickleandsuckle :

Well, if you said that you shorted it directly with the motherboard and the computer shut down instantly, I would say there's a big chance that only the motherboard was harmed and by shutting off, it saved the other components, but this is just an assumption. You can always take out the motherboard/ram/gpu and give them a scan to see if there's anything burnt that's clearly not supposed to be there.

sickleandsuckle · Sep 24, 2016

It indeed was the motherboard that shorted out. The new one has brought the PC back into commission.

Thank you everyone for your help!!

amtseung · Sep 24, 2016

sickleandsuckle :

Good to hear that it's just the motherboard. Be wary the next time you dangle live things onto other live things. They could... make children.

Wait. No, is that how it works?

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Shorted out my PC. How do I know which components were damaged?

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