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P4P800 on caught on fire?
9 Months ago I helped my younger cousin build a computer. Everything
went together just fine (I have built several machines AMD & Intel wihtout issue) Antec case & power Asus P4P800 P4 2.8 1GB of Memory (Kingston I think) Saphire ATI 9800 Pro Generic DVD/CD drive TEAC 3.5 disk drive Western Digital HD Nothing was overclocked...all at default/stock settings. Today, I get a call from his uncle saying that the computer caught on fire last night. Not raging flames engulfing the case, but that it was smoking and when he looked inside the case there were flames. He stated that when he unplugged the computer, the flames stopped (isnt the power supply designed to shut-off in this situation?) I have never had a computer catch on fire....any ideas on where to start my investigation? According to my uncle, there are burn marks on the motherboard near the center. I will be swinging by later tonight to see exactly what part of the motherboard he is referring to. Anyone had a similar problem or have any ideas on this one? TIA Ron |
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#3
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One possible scenario that occurs to me is that the CPU's fan failed and the
CPU really overheated. -- DaveW "ron" wrote in message m... 9 Months ago I helped my younger cousin build a computer. Everything went together just fine (I have built several machines AMD & Intel wihtout issue) Antec case & power Asus P4P800 P4 2.8 1GB of Memory (Kingston I think) Saphire ATI 9800 Pro Generic DVD/CD drive TEAC 3.5 disk drive Western Digital HD Nothing was overclocked...all at default/stock settings. Today, I get a call from his uncle saying that the computer caught on fire last night. Not raging flames engulfing the case, but that it was smoking and when he looked inside the case there were flames. He stated that when he unplugged the computer, the flames stopped (isnt the power supply designed to shut-off in this situation?) I have never had a computer catch on fire....any ideas on where to start my investigation? According to my uncle, there are burn marks on the motherboard near the center. I will be swinging by later tonight to see exactly what part of the motherboard he is referring to. Anyone had a similar problem or have any ideas on this one? TIA Ron |
#4
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I had a chance to do a brief inspection of the motherboard tonight.
The fire was based around USB coneectors 5&6 which were connected to the front USB ports on the Antec Case. These ports were not used according to my cousin, but I believe they worked when I finished builing it (I did have problems with the front audio connectors because the Sonata case doesnt use the intel standard...I left the wiring for the audio unplugged). So the question remains....how does a computer catch on fire at the USB pins/connector? I will double check to make sure that the USB wires were connected properly, but I doubt that's the issue (it would have either not worked and/or I would have seen a problem long before 6 months (I originally thought it was 9 months ago, but my receipts tell me otherwise). Any theories? I have heard of Antec mis-wiring the front ports on the Sonata case, but would this casue a fire....I thought it would just make things not work. If the power/ground wires got connected incorrectly, wouldn't that cause a problem up front....not 6 months down the road? Thanks for the input. Ron The only thing I see near the center of a picture of that motherboard, are some linear regulators based on MOSFETs. Asus does some of their onboard regulation, with quad op amps and MOSFETs, and if that is what failed, then some chip they are connected to must have failed, overloading the circuit. For example, you have an AGP slot near there as well, and perhaps something on the video card shorted and caused the power dissipation in the MOSFET to go up. I haven't traced the circuits down for those, but it is quite likely those linear regulatioo circuits are not protected against overload. Ondinary linear regulator circuits (three or five pin regulators), are protected against overheat, but when Asus builds their own onboard regulation using low integration devices, it costs them money to protect against every fault, so those MOSFETs could fry. If anything was to fail on the motherboard, I would have guessed "Vcore circuit", and that is in the upper left hand corner of the motherboard, between the I/O connectors and the processor socket. The Vcore regulator chips usually can sense an overcurrent condition and shut down, but that is only on their output side. There will be some fault conditions (like a MOSFET failure), where power coming from +12V could be what burns up the circuit. But that would be in the upper left hand corner of the board. When it comes to PSUs, they have an inlet fuse (for power coming from the wall), but their overvoltage and overcurrent settings on output, even if they exist, are so sloppy as to be useless. According to the ATX spec for power supplies, no flames are supposed to shoot out of the PSU in the event of a fault, but like the linear regulator circuit on the motherboard, there are going to be some faults (where the fault doesn't draw enough current to trip a protection device) that will cause a part of the PSU to overheat and smoke/burn. And for all you case modders out there, this is why you don't want a computer with a plexiglas window, or a computer that is completely made of plastic, as if the computer catches fire, there is a risk that a non-steel case could catch fire as well. A plain, beige colored steel case may be boring, but is more likely to at least contain the flames, if something like this happens. For most users, the smoke damage will be the most annoying part. And I have read accounts of flames shooting out of the fan hole of the PSU, so that does happen occasionally as well (by specification, it is not supposed to!). Obviously Ron, be careful with any components you recycle from that computer. For example, if the video card has a short on it, you could fry whatever motherboard you plug the video card into next. As you are planning to do, try to trace down what circuit has failed, as that will aid in determining what parts of the computer are safe to keep. For example, if the Vcore circuit in the upper left hand corner is intact, and no signs of damage, I would be tempted to reuse the processor. For the video card, pull it and inspect pins and copper traces, for any sign of a short. If the source of the failure was actually a MOSFET failing short on the motherboard, whatever part that got power from it, could now be damaged too. Paul |
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Dave:
Based on where the burn marks are.....I'd have to say no. Also, I think the ASUS board will shut off if CPU gets too hot. "DaveW" wrote in message news:dbWfd.18336$R05.11013@attbi_s53... One possible scenario that occurs to me is that the CPU's fan failed and the CPU really overheated. -- DaveW "ron" wrote in message m... 9 Months ago I helped my younger cousin build a computer. Everything went together just fine (I have built several machines AMD & Intel wihtout issue) Antec case & power Asus P4P800 P4 2.8 1GB of Memory (Kingston I think) Saphire ATI 9800 Pro Generic DVD/CD drive TEAC 3.5 disk drive Western Digital HD Nothing was overclocked...all at default/stock settings. Today, I get a call from his uncle saying that the computer caught on fire last night. Not raging flames engulfing the case, but that it was smoking and when he looked inside the case there were flames. He stated that when he unplugged the computer, the flames stopped (isnt the power supply designed to shut-off in this situation?) I have never had a computer catch on fire....any ideas on where to start my investigation? According to my uncle, there are burn marks on the motherboard near the center. I will be swinging by later tonight to see exactly what part of the motherboard he is referring to. Anyone had a similar problem or have any ideas on this one? TIA Ron |
#6
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I am not an expert (IANAE ?) but surely these things are designed so
that there isn't sufficient power available at the USB connectors that a short would start a fire. How would they get UL approval (and others) if that were so? In fact the power available at a USB connector for the external device is generally pretty limited, such that many devices need an external supply. It's possible that MB manufacturers have been increasing it lately because of that, but surely not to that extent? Leythos wrote: In article , says... So the question remains....how does a computer catch on fire at the USB pins/connector? I would guess that you shorted the power pins through something being connected improperly. -- -- (Remove 999 to reply to me) |
#7
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Hi, I read an article somewhere, I can't remember were, about graphics cards
becoming unseated and then catching fire. Thanks, John "ron" wrote in message om... Dave: Based on where the burn marks are.....I'd have to say no. Also, I think the ASUS board will shut off if CPU gets too hot. "DaveW" wrote in message news:dbWfd.18336$R05.11013@attbi_s53... One possible scenario that occurs to me is that the CPU's fan failed and the CPU really overheated. -- DaveW "ron" wrote in message m... 9 Months ago I helped my younger cousin build a computer. Everything went together just fine (I have built several machines AMD & Intel wihtout issue) Antec case & power Asus P4P800 P4 2.8 1GB of Memory (Kingston I think) Saphire ATI 9800 Pro Generic DVD/CD drive TEAC 3.5 disk drive Western Digital HD Nothing was overclocked...all at default/stock settings. Today, I get a call from his uncle saying that the computer caught on fire last night. Not raging flames engulfing the case, but that it was smoking and when he looked inside the case there were flames. He stated that when he unplugged the computer, the flames stopped (isnt the power supply designed to shut-off in this situation?) I have never had a computer catch on fire....any ideas on where to start my investigation? According to my uncle, there are burn marks on the motherboard near the center. I will be swinging by later tonight to see exactly what part of the motherboard he is referring to. Anyone had a similar problem or have any ideas on this one? TIA Ron |
#9
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I had a similar problem once, a long time ago
plugged a serial port on the joystick port and the cable went on fire when turned computer on(voltage to serial is bad)... maybe a similar problem with the USB connector could happen when USB port was plugged... "WoofWoof" a écrit dans le message de news: ... Leythos wrote: In article , says... I am not an expert (IANAE ?) but surely these things are designed so that there isn't sufficient power available at the USB connectors that a short would start a fire. How would they get UL approval (and others) if that were so? In fact the power available at a USB connector for the external device is generally pretty limited, such that many devices need an external supply. It's possible that MB manufacturers have been increasing it lately because of that, but surely not to that extent? The output can provide "a minimum of 500ma" according to this article: http://www.micrel.com/product-info/p.../mic2010.shtml .5 Amps is enough to melt small computer wires, and other things, if directly shorted, without proper fusing. Here is another from the same site that shows "short circuit current at 1.25 Amps max - well higher than needed to fry 28ga conductors and some foil traces. http://www.micrel.com/product-info/p.../mic2525.shtml Interesting .... then, unless things have changed significantly in the last few years, UL would require a fuse in those power lines if brought to an external connector (such as a USB connector). |
#10
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