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I built a new computer about a month ago, and I noticed that my speakers (which are old and malfunctioning anyway) made a disquieting static noise every time I turned my system on or off. I googled the problem and read something about how if the speakers are making that noise, it might mean that they're corrupt and that they're leaking excess power to the motherboard and may damage it over time. Today, the rear 3.5mm audio port on my case stopped working completely. No sound comes out using either speakers or headphones. The front port works just fine with headphones, and I haven't tried the speakers in that port.

This is probably unrelated, but I'll include this just in case it's relevant: Two days ago, my computer shut off suddenly, possibly due to a spark in the outlet, and wouldn't turn back on until I switched outlets and rebooted, then it detected an error in the HDD and repaired, but got stuck POST-ing over and over for a while before it came back up.

I'm using Windows 7 Pro and an Asus Sabertooth 990FX motherboard with an onboard Realtek ALC892 chipset.

What could be wrong here? Is it possible that what I read is correct, and my damaged speakers killed my sound card? Do you think there is any way to get the rear audio port working? If there isn't, would getting a PCI sound card be a way to get around this?

Update: The problem mysteriously fixed itself. I think Windows might have disabled the rear audio jack and I just didn't know. It's nice to know my sound card isn't damaged!

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Did the problem with the sound start before or after the power issue? If it started afterwards, the power issue is more likely to be the cause. –  ChrisF Mar 17 '12 at 23:31
    
It started before the power issue. –  Ana K. Mar 17 '12 at 23:41
    
@AnaK: post that as your answer, and select it when you can –  Journeyman Geek Mar 18 '12 at 8:28

3 Answers 3

Its unlikely but it depends.

Passive speakers certainly will not - they run at VERY low currents and voltages.

Active ones, its possible - you have higher voltages involved, a seperate power supply, and if somehow, there is a short between power and signal, or a surge through the speaker power supply and you have your power output somehow going out the signal input, it sounds like a recipe for very bad things.

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They are active speakers, and that's good to know for the future. It looks like my problem is resolved (see my comment on the previous answer) for now. Thanks for clarifying this for me, though. –  Ana K. Mar 18 '12 at 2:05

No, external speakers only use the signal provided by the computer's audio output. If the speakers have problems, it's highly unlikely they are generating any voltage on the computer's sound card's output that would cause damage. About the odd speaker noise, try to isolate if it's actually a noise being generated by the sound card or speakers. Use some headphones to do this. Check in the sound control panel that the rear speakers are enabled. Windows 7 might have turned that jack off. For the spark, it sounds like a blown circuit breaker. If you lost power to the pc, tha would probably cause that disk error thee next boot, as the power loss probably corrupted that file (that was then repaired). Sparks at plugs aren't a good thing. That's more a concern then any thing else. But to convince yourself that any computer problems are unrelated to the speakers and previous problems, try using headphones for awhile and compare observations.

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I think you were right in saying that Windows 7 turned off the jack, because now, after plugging in a different set of speakers, the original speakers work in the rear port again. I'll try using headphones to see if the static noise is generated by the sound card, but it looks like my original problem is resolved. Thanks for your help. –  Ana K. Mar 18 '12 at 2:04
    
External speakers are often "active" -- with a separate power supply -- and these can (in theory) damage the computer port. –  Daniel R Hicks Mar 18 '12 at 3:11

I did experience one case where a set of speakers with a poorly-designed "wall wart" caused an overheating situation that nearly melted down the speaker wire. The "wall wart" grounded one side (the "wrong" side) of the DC power wire, and this created a large ground current through the speaker wire.

In theory a malfunctioning active speaker could put enough voltage on the center pin of a speaker wire to damage the computer audio port.

It's also possible that a "dead short" on the audio port could damage the computer's internal circuitry, though a well-designed computer would protect itself from this.

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