Cap on P5K Blew But Still Works? Dangers?

A

aldamon

Supreme [H]ardness
Joined
May 24, 2000
Messages
6,670
Hey,

Tonight I heard a loud bang and it turns out a cap blew on my P5K. Supposedly this is a common problem with the P5K and overclocked quads. The strange thing is it still works. In fact, I was running Prime 95 at the time of the explosion and the machine never missed a beat. This might be a dumb question, but can I get electrocuted or something from the exposed innards? Also, am I risking a fire if I keep using the board? Here are some pics:

unraveled.jpg


cap.jpg
 
Thank goodness for 3-year warranties. ASUS is taking care of me.
 
Really not a good idea to continue using it like that without repair/replacement. It may still work but if what's left of that cap were to short out there could be complications. I suspect OC'd quads cause that vrm heatsink to get quite hot; the cap isn't particularly well placed to avoid being heated up - just goes to show us that even solid caps have the potential to fail catastrophically in certain situations.
 
it looks like that cap may have left a dent, when they go, they go with quite some force.. see if you can find the impact point and get pics
 
That cap was part of the CPU voltage regulation circuit and will indeed contribute to stability while OCing. The system shouldn't necessarily implode or something like this, but it may run less stable when OCing and crash more often.

Replacing it/RMAing the board isn't a bad choice :)
 
Hard and Confused said:
You're not [H]ard untill you push hardware to its Outter Limits
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The funny thing is, I folded with the machine @ 3.5 Ghz @ 100% load for 1.5 years 24/7 with no problems. Lately it's just been a gaming rig that I rarely turn on. Last night, I was only trying 3.3 GHz with auto voltage because I was experimenting with quieting the machine down and using less power and it blew after about 5 minutes! Weird. Must have been its time to go.

Thor said:
it looks like that cap may have left a dent, when they go, they go with quite some force.. see if you can find the impact point and get pics
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Yeah, the sound scared the crap out of my wife and the dog jumped out of her bed. I will look to see if I can find the impact point. Glad I had the side of the case on.
 
I would definitely not use it, it takes less than 2 amps to kill a person, and their is a lot more amps than that running through a typical 12 volt rail.
 
Exeodus said:
I would definitely not use it, it takes less than 2 amps to kill a person, and their is a lot more amps than that running through a typical 12 volt rail.
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true, however, this isnt a 12v rail, its on the cpu voltage regulation curcuit, it may be a 16v cap, but it was probably only seeing 2v tops (fed by the 3v rail, after a regulation curcuit), it was also only 724uf, or just over .7 amps or 1.4 watts, considering its location it was probably just a buffer on a secondary supply for that PWM., i still wouldnt reach in there and touch it while its on however... but who would do that...
 
Exeodus said:
I would definitely not use it, it takes less than 2 amps to kill a person, and their is a lot more amps than that running through a typical 12 volt rail.
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35 microamps (millionths) across the heart can cause death.
 
Exeodus said:
I would definitely not use it, it takes less than 2 amps to kill a person, and their is a lot more amps than that running through a typical 12 volt rail.
Click to expand...

amperage is a product of voltage and resistance. In most cases, 12 volts is not enough to cause even the sensation of shock because the body's resistance is incredibly high and current cannot overcome it.



OhMyGod said:
35 microamps (millionths) across the heart can cause death.
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Yeah, but you still have to cut the person open to get to their heart first. It's much easier to just drop a toaster into a bathtub.
 
ryan_975 said:
amperage is a product of voltage and resistance. In most cases, 12 volts is not enough to cause even the sensation of shock because the body's resistance is incredibly high and current cannot overcome it.

[..]

Yeah, but you still have to cut the person open to get to their heart first. It's much easier to just drop a toaster into a bathtub.
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Pretty much. The resistance of dry human skin is a few MOhm (mega, as in million). To bridge that the voltage (potential) would have to be a few kV. Only if 20+ mA then passes straight through the heart is there a possibility of cardiac arrest. The 'one hand' rule was invented to limit this possibility. See people who have been hit by lightning and survived.

The experiments Mythbusters did on this are actually quite informative, including the 'toaster in bathtub' one :)


Related, I have been shocked many times over the past years by 230VAC (outlets, wiring) and 12VDC (car batteries). I'm still alive :)
 
Don't ask me why,but I lol'd pretty hard at those pictures. All kinds of scenarious running through my head.
 
So i have my case window in my view- pointing directly at me... if a cap were to explode with force off my mobo...what are the chances of it breaking my side window and hitting me in the face :(

i hope it isn't THAT much force
 
Probably not enough force to do much more than crack the window. If your board isn't prone to this problem (like the asus), you don't need to worry about it.
 
Zero82z said:
Pretty much zero. It's a capacitor, not a bullet.
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Indeed, the amount of energy contained in a fully charged (3300 uF or thereabouts) capacitor is only a minor fraction of what an explosive like gunpowder contains. I'd be more afraid of cutting yourself on sharp edges while messing around inside the case :)

Things don't get dangerous with caps until you hit around 1 Farad or more and even then the danger is mostly from getting zapped, not from it exploding due to a short. The average pressured canister is far more likely to be lethal, as illustrated on Mythbusters when they made one punch a hole through a brick wall :p
 
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