Pc started smoking

[rh71]

Generic case with Gigabyte EP45-xxxx Mobo which is older. Kid was playing games on it when all of a sudden it started smoking so mom turns it off. The side cover is always off BTW. I come home to troubleshoot and upon powering on, I can hear something simmer and notice it's coming from one of the case pins that connect to the mobo. In this case it was the 4-pin connector for the case speaker (which never worked btw). The plastic insulation around it is burned off quite a bit throughout all the way toward the speaker itself, but it's only this pin. The HDD and other led pins aren't affected. No foreign debris found.

So I removed that 4-pin connector from the mobo connection figuring it's not necessary anyway but now the thing only powers on for a few seconds and immediately shuts off. Is this a psu issue from the start? Sending incorrect voltage causing the meltdown? Or is the case and it's various wiring to the mobo the culprit?

 

[ClockHound]

This is why I enforce a strict no-smoking policy in my office - for all my systems. ;-)

Sounds like the PSU might have instigated the magic smoke release ritual. But, it could have been encouraged into the burning frenzy by a short on the MB and/or wiring.

How old is the PSU? Can you see any bulging caps inside?

 

[C1]

A case speakers is not only a low current device, but it is also not a direct current device as it would normally burn up quickly.

The whole thing sounds like the speaker connector might have all along been pushed over the wrong set of MB terminals (ie, cross terminaled so to speak which is probably why it never worked to begin with) now ultimately resulting in a MB failure.

Check and verify all of the original connections for the case wiring to the MB against the MB installation guide.

If the issue still persists (ie, MB shut down), you may have to pull the whole system down to a minimum configuration and start with a new PSU to determine if the system can be made to sustain normally. If not, then the MB in all probability needs to be replaced, but you probably could pick up a replacement on eBAy.

 

[rh71]

So this is definitely not a case and its pins being the problem?

The mobo pin marking says speaker and one side was marked positive and the other negative. So you're saying perhaps I swapped pos and neg (black = neg) which caused this? And now the mobo is fried?

Even if I get new psu / mobo, do I need to have the speaker plugged in? That's done-for I suspect.

 

[ClockHound]

No, does not matter which way the polarity goes. Unless you care about absolute phase of your pc beeper speaker. And, no you don't need the speaker plugged in.

But, if the speaker connector was connected to the MB speaker header, then suspect it was an innocent victim of something more serious - like a failed PSU or short elsewhere on the MB.

 

[aigomorla]

i cant see a speaker connection smoking.
There just isnt enough current that runs though that to cause it to smoke.

Infact nothing there would cause enough current, the LED headers all run at 3V, and very low amperage, the reset and on off switch was designed to be shorted.

I also think something bigger maybe your issue.

Also correct me if im wrong, but a speaker wire is spaced out with 3 blanks in between.

I cant see how it would catch on fire..

Are you using any SATA / 4PIN molex adapters?
These are notorious for smoking... in fact i have had 2 of them go up in smoke..

These pieces of junk should NEVER be trusted... especially the ones which are molded on the SATA side.
Like this...

But that cable will burn because of the 12V lines....

IF your PC smoked.. i would recheck all the sata / power cables you have.

 

[rh71]

i cant see a speaker connection smoking.
...

I don't run any SATA other than the SSD and that looks completely fine. Every cable in there does except for the speaker line. Here's a pic of the case wires and you can see only the speaker line is charred. In fact it's no longer connected to the speaker itself. I'm assuming it charred off, unless it was removed somehow (pulled off accidentally) and then it contacted the metal case causing a short right into the mobo? Could that have happened? Speaker line is red/black. The other red/black that looks fine is the power switch line which still works fine (read below pic).

I used another very old mobo to prove that the PSU is still in working condition, as well as that power switch line (same ATX case and power switch - red/black wire that still looks good). The replacement mobo turned on and stayed on. So unless I'm not troubleshooting correctly, the Gigabyte mobo appears dead - it comes on for a few seconds and then off when the power plug is inserted to the back of the PC. But nothing when I hit the case power switch.

 

[aigomorla]

what is that white thing u have bundled?
is that a garden tie?

again i am completely lost in how your speaker wire went up in smoke like that.
You are correct tho, it is the speaker wire which caught fire.

 

[VirtualLarry]

Solution to smoking? Try Chantex. /s

On a more serious note, that IS rather... unusual... for a PC speaker to melt wires like that. Unless it was plugged in wrong, or a wire frayed and contacted a power source, that never should have happened.

I would suspect PSU first, and then mobo. Perhaps the ground plane became energized, somehow.

 

[rh71]

what is that white thing u have bundled?
is that a garden tie?

Yes and the case came like that. I never touched that.

I did verify it was plugged in negative to black so that wasn't the issue.

 

[Ichinisan]

I've encountered PCs that were destroyed by vaping.

In a vape shop, deposits accumulate inside and eventually shorts something. Then you get smoke.

Vaping leads to smoking.
Smoking is bad.

 

[rh71]

UPDATE:

I re-seated all the PSU cable connections to the mobo and now it's powering up fine. *shrug* Only the PW Switch and PW LED pins are connected from that area. We'll just have to wait and see if there's another smokeshow. Maybe I just had to threaten it with an old mobo before it knew what was good for it.

 

[VirtualLarry]

I re-seated all the PSU cable connections to the mobo and now it's powering up fine. *shrug*

Weird. Sometimes, PCs just need some TLC. A good unplugging and re-plugging.

Maybe that reset some auto-resetting fuses too, you need to remove power from them entirely to reset them.

It's still possible that the PSU is on the way out, how old is it?

 

[rh71]

Froze after a bit of usage. Ordered a new PSU. It's over 10yo. Guess it wasn't the ram that I replaced under warranty for that freezing problem, although the problem went away when I removed 1 stick. Power delivery issue perhaps. Old components = so much fun.

 

[VirtualLarry]

Froze after a bit of usage. Ordered a new PSU. It's over 10yo. Guess it wasn't the ram that I replaced

Yeah, I suggest replacing them every 5 years, unless they have Japanese or Solid capacitors inside, and come with a 7-10 year warranty.

Some people like to "run them until they die", but I consider that kind of risky, unless it an older / browser box that can just be replaced, and there won't be any data-loss if it catastrophically fails due to PSU failure down the road. (Backup your pictures and documents, people! Flash drives are CHEAP!)

 

[ClockHound]

Flash drives are CHEAP!)

And a perfect match for a smoking PC!