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Is Your Computer a Fire Hazard Waiting to Happen? 518

Posted by Cliff
from the smoke-alarms-and-fire-truck-sirens dept.
whoppers asks: "I'm sure we've all had our share of computer fans die, but what happens if your box is running while you're at work and several fans go out? My in-laws spare TigerPC AMD K62-400's power supply fan just went out about two hours ago, and the thing was blazing hot. A little poke to the blade, and it started up again, but shouldn't these things be made to stop if the fan stops for any reason? I'm starting to wonder if I should start leaving my box off when I'm away for a few hours. Since it's usually wide open, I don't see too much harm, but these cheap boxes that never get opened and cleaned have to be a hazard right? I can't afford a halon system in my office just yet. The only link I found related to this is here and should a few more people read this, here's the cached version. Does anyone have any thoughts or stories related to this?" The fact that this article appears on July 4th, when most Americans will be lighting fireworks is purely coincidental. That doesn't change the fact that the submittor raises a very good point. A general rule of computers is: the older they get, the more dusty they are and dust bunnies and their denser cousins are highly flammable. Unless you can keep such machines clean, it' is probably safer to leave them off.
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Is Your Computer a Fire Hazard Waiting to Happen?

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  • Hmmm (Score:5, Funny)

    by shr3k (451065) on Thursday July 04, 2002 @01:37PM (#3822805) Homepage
    The only link I found related to this is here and should a few more people read this, here's the cached version.

    A link to the cached version? Come on, this is Slashdot. What's the worst that could happen?
  • So what??? (Score:3, Funny)

    by josh crawley (537561) on Thursday July 04, 2002 @01:38PM (#3822812)
    Yeah, old comps do get dusty inside. However, even if the fan quits, it's still not a problem. That bit of dust is flammible, but the metal aint. There's a fireproof box around those bunnies. ANd once it smolders some, it'll burn out most of the O2 (since the fans dont pump air cause of dust). There goes your "fire hazard"

    The only thing is it's a boring news day.
    • I don't know about you but the face plate on my box is plastic and I usually have other things sitting on the box like jewel cases and maybe some papers.
    • Re:So what??? (Score:3, Interesting)

      by Beliskner (566513)
      ARGH!! Another problem that can be solved with a component costing 10 cents - a thermal fuse. All you software engineers trying to read hardware interrupts from fan speeds and temperature sensors. What if the FAN_SENSE wire shorts with the PSU's AC output - even if the fan stops working it'll still look like it's giving 60rpm. Leave this to the electrical engineers now go back to Java or VB software peopl.
  • ASUS (Score:5, Informative)

    by selderrr (523988) on Thursday July 04, 2002 @01:39PM (#3822817) Journal
    the new ASUS motherboads have COP : CPU Overheating Protection, which switches off the machine when temp goes baloony.

    And they're damd fine MoBo's too...
    • Re: ASUS (Score:3, Interesting)

      by Black Parrot (19622)

      > the new ASUS motherboads have COP : CPU Overheating Protection, which switches off the machine when temp goes baloony.

      I have an ASUS board a bit over a year old. I do intensive number crunching on my home machines, with some jobs running over a week of continual 100% CPU time. Being AMDs, they tend to run kind of hot, too, so sometimes I put a room fan blowing along the wall behind the boxes' exhausts.

      At any rate, one warm day I had the A/C set kind of high and the room fan aimed elsewhere, and one of the boxes overheated while I was out to lunch. But the board halted it for me. When I came home it was making a horrible alarm sound, and unfortunately I had to reboot because I couldn't figure out how to make it restart after the alarm, but at least I didn't get a fire, nor even any overheat damage to the CPU.

      BTW, Linuxers/BSDers who have temperature sensors on their motherboards may want to run lm_sensors [lm-sensors.nu] and a display such as gkrellm [wt.net] in order to keep an eye on your system temperatures when you are around.

    • Re:ASUS (Score:2, Informative)

      by Anonymous Coward
      not to mention that all intel chips since the Coppermine Pentium 3 have had auto shutdown on overheat. The new P4s will actually underclock themselves if they overheat, and P3s on overheat will automatically lock hard.
  • by shepd (155729) <slashdot,org&gmail,com> on Thursday July 04, 2002 @01:39PM (#3822818) Homepage Journal
    You have nothing to worry about. They test for things like the fan stopping.

    Eventually, when the heat gets too high, the power supply will either shut off or destroy itself.

    The UL/CSA logo (if its genuine -- many cheap power supplies don't put on genuine labels) "guarantees" the power supply won't be dangerous to you. A flaming power supply would be, obviously.

    Hope that allys your fears!
    • As the computer overheats, it will draw more power from the power supply. If the power supply is properly made, it should blow the fuse when that happens. However, not all are properly made. I have seen some with no fuse at all.
    • The fire supply does not have to catch fire to make one, and that's the point of the submission. Take the spare hard drive wires on a running computer and rub them in some steel whool. The whool will burn, as may your dust bunnies, noise abaitment foam or any other combustibles in your case, like dust bunnies. If you create the right conditions of insulated heat generation, oxygen and combustible materials, you will have a fire every time. If your load of combustible materials is large enough, the fire will spread and you will burn your house down.

      I see a few steps I can take to improve my shelf o'computers. I'm going to move my printers to another table, remove excess wires and monitors, and other non esential materials. The insides of my boxes are clean. Smoke detectors and insurance can't hold a candle to prevention.

  • Maybe insurance companies should offer discounts to those of us with common sense enough to buy and configure motherboards that have a "Power Off on High Temperature" option in the BIOS. Haven't these motherboards been available for a long time?!
    • Maybe insurance companies should offer discounts to those of us with common sense enough to buy and configure motherboards that have a "Power Off on High Temperature" option in the BIOS.

      The fact that they don't is probably sufficient indicator that the incidence of overheating motherboards burning people's houses down is very low indeed.
  • by eagl (86459) on Thursday July 04, 2002 @01:40PM (#3822829) Journal
    At work they made a policy that ALL computers will be completely shut down at night after a monitor caught fire one night and burned out an office. Normal hardware shouldn't catch fire even when old/crusty but there's NO guarantees when the hardware is defective to start with.
  • Fire hazard (Score:2, Interesting)

    by SpatchMonkey (300000)
    Many modern motherboards power automatically power down when the CPU gets too hot, but that is just the CPU .. I think the greatest danger in modern computers is the power supply.

    At work we recently had a problem where a paperclip fell inside the grilles in the power supply and shorted something out, causing power surges which trashed the rest of the computer, which wasn't nice.

    But what was worse was the smell of the thing, it was really nasty. When capacitors burn due to having too much current put across them, they release all sorts of nasty toxins and also fibres which can stick to your clothes and make them smell for ages. Or even worse, stick to you skin and eyes and burn or blind you.

    It's not just fires that are a hazard. Computers, and indeed most electronic devices, consist of many environmentally unhealthy and hazardous chemicals.
  • by Anaplexian (101542) on Thursday July 04, 2002 @01:42PM (#3822836) Journal
    If I had a webcam, I'd post a link to a photo.

    I'm running Win 98 on a Cyrix M2 233MHz overclocked to 300MHz (came when I bought it).

    I paid 2500 rupees for the processor, [ 1 US$ = 48 Rupees - do your math], and thus don't really care much about it. :)

    Anyway, it's 40 degrees here in Delhi, I don't have an AC, and my CPU Fan's bust for *over a week*. And it's happened several times before.

    What do I do? I take off the Hood, Put my ceiling fan to "Maximum" and keep on Photoshopping.

    I'm a comp Sc student, and I know what I'm doing is insane.

    but, Hey, As long as it's running, Who cares?
  • Always open? (Score:5, Interesting)

    by Amarok.Org (514102) on Thursday July 04, 2002 @01:43PM (#3822850)
    Since it's usually wide open, I don't see too much harm, but these cheap boxes that never get opened and cleaned have to be a hazard right?
    It should be noted than a open computer case will likely run hotter than one properly closed up.

    Fans are designed to move air - like any fluid motion, air will move along the path of least resistance. In the case of a case fan, where the case is left open, you're pulling air from a very small area right in front of the fan before exhausting it out the back. The heat generating components (CPUs, hard drives, video chips, etc) tend to be far enough away from these fans that you'll see almost 0 airflow over them.

    I used to work for a major hard drive manufacturer, and would get complains from users who said our drives were running too hot. Quite often, they said "I even leave the case off, and it's still too hot!". Many times, just putting the case on solved their heat problems. By creating essentially a duct for the air to flow through, the fan was able to pull air from the front of the case, across the heat generating components, and then exhaust it out the back.

    In the case of components with their own fans (CPUs, video chips), this is still important - while you've exhausted the hot air from around the component, without a properly functioning (read: case on) case cooling system, that hot air is never removed from the general area around the component, and just gets sucked back in on the intake side of the fan.

    Just my $.02.
    • Which a great deal of them aren't. With most of the computers I've owned, if I took the side panel of the case off, the CPU ran a full 8-10 degrees C cooler than with the case fully closed. This is primarily because the poor case cooling meant that the air inside the case was 10 C or so hotter than room temperature, so removing the side panel let the CPU fan suck in cooler outside air to blow on the heatsink (since the CPU fan is at 90 degrees to the motherboard, it's good at sucking air directly from outside if the side panel of the case is off).
      • I've found that just laying my case down lowers the temp (only by 1-2degs to be honest). I figure this is due to the fact the CPU will be facing upward and so the heatsink is working more efficiently.

        I've also found that adding a fan to the top of the case to pull the hot air out (on upright cases) makes a BIG difference, especially on smaller cases designed for the MATX boards. I had an athlon in a small case that was running at 60-65degs and very unstable until I cut a hole and put a fan in the top - it dropped the temp to 50-55degs and hasn't crashed since.

        I think the biggest single difference I've made was adding a Coolermaster "Heatpipe" heatsink to an Athlon - that thing knocked 15 degrees off the CPU temp immediately! I had to remove it again though, as the noise was unbearable... It makes a nice-looking paperweight though!
        Also little things like tidying up a rats-nest of wiring and putting dummy plates over unused expansion slot cut-outs in the case helps.
    • Of course, if the reason the case is off is so that you can point a desk fan at the innards, that's a different story. A friend of mine did this for a while, because the guts (drives, mostly) ran too hot; it apparently helped a great deal.
      • Re: Always open? (Score:2, Informative)

        by Antity (214405)

        Of course, if the reason the case is off is so that you can point a desk fan at the innards, that's a different story.

        ... the problem being that if something really catches fire (quite common for electrolyt capacitors), the sparks will have great fun flying all over your (wooden?) desk with the latest printouts of your source code all over it.

        I also did this for quite a while before I thought about it. Now I guess that this is even more dangerous.

  • by dalassa (204012) on Thursday July 04, 2002 @01:43PM (#3822851) Journal
    Even if the computer never over heats dust and oils and other icks can still kill a computer. I once was trying to fix a women's computer that had stopped. I opened up the case and the entire motherboard was covered in oil and fur. Turned out she let her cat sleep on it all the time and never cleaned it. All that direct exposure to animal bits just killed it. She had to buy a new computer.

    I now religiously check the dust levels of my computers.
  • by I_redwolf (51890)
    Just like anything else give it a simple cleaning. I'm sure every now and then you take a simple duster to some of your stuff. It's very easy to buy a can of compressed air and then use the compressed air to clean out the dust bunnies. Once every 6 months or so and you should be fine. There are also cases that prevent this very thing, as it's too hot for me to be on my computer right now I'll just explain the case I have. I have a Lian Li that I bought from thinkgeek it has a filter system in the front. A filter is placed above two high speed fans (who's speed can be set) that catch dust and that is removeable and cleaneable. Dust still gets in the case but it's alot less and my cleaning time is really only annual if I want. Even if you don't have fans in your case electricity can attract those dust balls at the foot of your box very easily so it's not just a matter of fans or moving parts it's really just a matter of cleanliness.. Smoking, dustballs, dirt, etc can all cause problems.. but a regular dusting helps.
  • They are screaming:"Computer nerd started fire and takes down entire block of houses!"
    I've always questioned this myself since I always leave my computers running and the athlons keep getting so hot. My parents used to hate it when I left home and left the computers running, but now I've got my own place it's much bigger an issue than before. I do like the fact that most of my Macs hardly use their fans, or don't have fans at all. This keeps me a little less paranoid when I'm not at home. It's also a bit of a problem that in my place (small town in The Netherland) does not have broadband access and I have no possibility at all to check up on my systems when I'm away. Anybody got a few hints fow me?
    • by znu (31198)
      I believe all Mac models made in the last few years will automatically switch themselves off if they overheat. This dates back to the Blue & White G3, where you could invoke thermal shutdown by running too long with the case door open (which prevents proper airflow over the processor).
  • I have an IBM Thinkpad A20P. Great machine, but one day I was typing on it and felt unbelievable amounts of heat coming off the top of the keyboard. Just as I was remarking to my coworkers about it, the machine halted to a black (no, not a blue screen; I can't remember if I was booted into Linux or Win2K at the time). Anyways, I power-cycled, and the BIOS halted again with a "Fan Failure" error. Aha. So I whistled it over to the service depot (under warranty) and they found that a long human hair had been sucked into the air intake and wrapped itself around the fan, halting it.

    Thank you IBM, for building systems that watch for this kind of thing. One step friendlier could have been a user warning (through a BIOS video overlay) that said "HIGH TEMPERATURE ALARM - POWERING DOWN IN 10 SECONDS" or something, to allow a user (if present) to save some of their work. Anyways, at least it didn't keep running and cook my CPU, hard disk, and everything else they pack into such a small space on these notebooks.
    • Actually some processors would be well fried by the time it takes for it to shut down cleanly and give a warning. Just a few seconds might do it if the heatsink and fan falls off an Athlon for instance.
      I don't think this is the case here, but it's just food for thought.
  • I used to work in an engineering shop. The place was dirty and dusty as hell which caused computer equipment in the engineering office (read "big shack in main building") to become dirty and dusty as hell. One day something was giving off a burning plastic smell...

    Phil: What's that burning plastic smell?

    Fred: It's your monitor, it's on fire.

    Phil's monitor had caught fire. Of course the monitor was destroyed but people were around to put it out and keep anything really bad from happening.

    Two months later...

    Phil: What's that burning plastic smell?

    Fred: Your monitor is on fire again.

    Phil's replacement monitor had caught fire. That was the last computer monitor fire they had that I know of. It didn't stop Phil from leaving his monitor on every night when he went home from work.
  • I too had my share of dead fans in the past 2 months. 3 fans (out of 4) died on my 3 years old computer: PSU fan and both CPU fans (dual setup). Only the front fan survived (as of yet).

    The thing is, even without sensors, I still have caught the failing PSU fan. When it stopped, the PSU got hotter (as what happened to the poster in-laws), but after reaching a certain temp it just shutdown itself. And I couldn't get the computer to restart immediately after (before knowing what was causing the trouble), since the temperature was still too hot for the PSU to allow power to flow. I'm talking about a cheap 250W DTK ATX power supply from 3 years ago. After letting it rest a little, I retried, and while booting it shutdown again. The third time I tried to access the something on the back, and then noticed that no airflow was going out of the PSU.

    For the 2 CPU fans, the motherboard RPM sensors saved both my CPUs (and the fact that I was watching them at the right time).

    On a modern computer (where fans can and will die given enough time), a plethora of programs can be run in the background to check the RPM of fans and the different temperatures in the system. Just make it alert the user (or shutdown if no action is taken in x time) in case of one parameter going outside it's normal range. Check overclocking sites for info on that, since they usually tend to have more problems with that then plain desktop users.

    Also, the MTBF for cheap DC fans is usually around 20000 hours. That means a bit less than 2 hours and a half. Either replace them beofre, check them cautiously before that mark, or get some higher quality fans (which will tend to be quieter, too).

    Another solution is to go with watercooling (but then, if there's a spill AND you're fluid is conductive, the fire hazard is still present). You've only got a pump and a fan (for the heat exchanger) which can die, rather than 3+ fans in a typical computer case (yea, I know, SPOF, but they're more robust).
    • Also, the MTBF for cheap DC fans is usually around 20000 hours. That means a bit less than 2 hours and a half. Either replace them beofre, check them cautiously before that mark, or get some higher quality fans

      An interesting thing to keep in mind is that only about a third (actually e^1 for those who care) of all parts will survive with no failures until the MTBF.
      • I thought it was a half, but it's still a figure of "if the part is still good at that time, better have a spare because it's gonna die sometime in the future".
  • Danger with Old PCs (Score:5, Interesting)

    by shr3k (451065) on Thursday July 04, 2002 @01:49PM (#3822905) Homepage
    My friend has an old IBM PS/1 that's a 486 with a Pentium Overdrive chip that he uses as a print server. While he's been away, I've had to fix the machine. It was scorching hot to the touch and I thought the power supply was going bad.

    After considerable effort, I removed the power supply with the intention of replacing it with another AT one that I found. Unfortunately, the power supply had extra proprietary connectors and the replacement one didn't, so I was left to figure how to fix the original one.

    I took a closer look and I saw nine (9) years (!) worth of dust clogging the power supply fan, thus blocking its motion. Ignoring printed warnings as "Caution! Shock Hazard" and "Warning: No User Serviceable parts inside", I carefully opened the power supply and removed the fan. Fortunately, the fan had a plaster connector for easy plugging/unplugging (as opposed to being soldered directly to the board).

    So I removed the fan with easy and scraped (yes, SCRAPED!) the crap off of it and wiped it down. Then I applied WD-40 to the bearings to get the fan blade with more ease. I had to help the WD-40 spread by using a screwdriver to turn the fan both directions. Finally, after 20 minutes of effort, the fan blade was turning reasonably well with I'd tap it, so I put it back in, reconnected it, and reassembled the power supply.

    Once the computer was put back together, I turned it on and felt for heat. Not alot. For the first time in a while, there was ventilation coming from the back of the power supply and the system was running much cooler than before.

    So, let this be a lesson to you. Make sure you regularly (yearly?) clean your fans off, removing the dust before it cakes on. Make sure that you do this to any older PCs you have or are about to obtain.

    Otherwise, your system will run dangerously hot and only bad things can come of that.

    • Is wd40 flammable?
  • KAAABOOOOOM!!!! (Score:2, Interesting)

    by MrIcee (550834)
    While many computers do have thermal shutdown circuits (which can themselves be annoying)... in my experience it isn't the computer itself that is the most dangerous component.

    Twice I have had a (rather large) UPS explode. When a UPS goes, it goes spectacularly. Really explodes. Smoke, fire, huge BANG. Talk about dangerous. We actually had one UPS disintegrate into pieces... luckly nobody was close at the time.

    Monitors can also be pretty spectacular. Where I live we get 150 to 200 inches of rain a year... needless to say, it's frequently damp. I've had monitors, when turned on, explode (luckly never the screen though, only the power supply). We tend to leave all our equipment on, and baking, to avoid this - but still we go through a monitor a year (we are starting to replace them with LCD, we'll see how those stand up to the elements).

    But the worst were definatly the UPS - especially since they are near your feet - they can be very dangerous indeed.

    • Twice I have had a (rather large) UPS explode. When a UPS goes, it goes spectacularly. Really explodes. Smoke, fire, huge BANG. Talk about dangerous. We actually had one UPS disintegrate into pieces... luckly nobody was close at the time.

      So do power supplies. I had a very nice 386DX which I bought long ago. I still have it, sort of. It started life as a 386DX/25 2mb ram/62mb hd. It then became a 486DX2/66/8mb/2.0gb in 1998. A few years before it became a 486, the fan in the power supply went. I thought nothing of it, but I got it to work again. I then upgraded it to a Celery 667/288mb/20gb.

      The first time I tried to power it up, the power supply exploded. Literally exploded, there was a big bright blue flame coming from the supply, it was a little bigger than it should have been, and it left a large black mark on my wall, which is still there.

      That day, I learned that a AT case was $45, and a AT power supply was $40. So I bought the case. Hence the "sort-of". Up till that point, every part in the computer (except the case/PS) had been replaced. Now all of it has.
  • My computer has three fans, i installed some extra since the one fan on the power supply died and my computer started to become unstable. I started to get Compile errors, i destroyed half of my Memory or so memtest86 told me. machine temperature got over 50 degrees in the box, the cpu was at 70 degrees celsius.

    I bought two extra fans and a new power supply the machine is running like a charm ever since :)

    You wont see three fans die at once, better save then sorry.
  • Dust filters (Score:5, Insightful)

    by scott1853 (194884) on Thursday July 04, 2002 @01:52PM (#3822920)
    How come nobody has made a case with an air filter on it so you only have to brush off the filter every month instead of taking a can of air to the box?
    • Re:Dust filters (Score:5, Interesting)

      by dattaway (3088) on Thursday July 04, 2002 @02:24PM (#3823095) Homepage Journal
      I have a little story about air filters and overheating...

      At work, one of the PM guys wanted to protect all the large, expensive DC motors on the manufacturing lines with an air filter on the blower motors. Well, next thing we know, there's filter fabric zip-tied to every blower opening on every motor.

      The fabric didn't restrict the air flow too much. Until a week later, when the grease and dust in the air clogged them up. Then the problems really started showing up. If you look up the prices of DC motors in supply cataloges, you may notice the prices run up to $100,000 each for the large 500 horsepower models. It seems our desire to protect these babies created an intense smell of burned enamel. When you have about 300 of these motors laying around, many in obscure places, we learned its better to have dust caked up inside the motor than have an undersized filter trying to protect it.

      So, the question is, are you going to change or clean this filter on a regular basis?
  • I don't see a great fire hazard here. Sure, dust bunnies are flammable, but it would take an extremely hot processor to ignite them, and even then it would be more of a quick flame than a real fire. I just can't see the electronics or the case catching fire.
    Bottom line: You might lose your PC, but it will be a very quick and self-contained fire. And considering how extremely unlikely it is to happen, I'd say don't worry.

    It just ocurred to me that water cooling might double as a great fire-extinguisher... since a fire in the case would probably sever the hoses. Then again, if you're water cooling, your processor will never get that hot... never mind.
  • Seeing as how you have an AMD I'm thinking your motherboard doesn't have buil-in protection against overheating. I'm not too familiar with hardware but isn't the chip the only thing that gets really hot? If so when the fan goes off either your chip should slow by its self or the motherboard should slow it down for you, in either case your chip shouldn't overheat.

    As to the dust being a fire hazard and assuming it is still a risk at normal operating temperatures (which your box should not exceed by much for the previously stated reason), the only real solution would be to clean it out.
  • Thats one thing that i like about the Intel Pentium III and IV processors. If the CPU fan were to die on the PIII chip, the processor would simply halt all processing if the chip temp. got to high. In the Pentium IV processors, if the fan dies, the CPU will actually down clock itself until it reaches a safe temp. to keep running at. Although I dont know what you could do if the PS fan were to die; i wonder if you could rig something up similar to the fail safe in the P3 chip that would simply shut the power off if the temp. got to high. In any case, the one thing that i did that helps keep all those dust bunnies out of my case was to install washable filters [startech.com] on all the fan spots. That makes it a hell of a lot easier to clean, plus i dont need to clean out the inside of the case anywhere near as much anymore.
    • What if the power supply fan dies, and the power supply itself overheats and dies? Thats a bitchen place to have a fire, as you have a nice high voltage (120ac) high current enviroment to feed it. Thats why i own a portable air compressor (one of those 150$ jobs). Its great for showing up at the client's site and blowing out all their machines.
  • Poll (Score:4, Insightful)

    by Kingpin (40003) on Thursday July 04, 2002 @01:54PM (#3822938) Homepage
    Instead of chasing windmills, let's have a poll on this.

    Spontaneous computer combustion:

    ( ) Seen it
    ( ) Heard of it
    ( ) Heard of someone who heard of someone who...
    ( ) Nope

    My point is, is this really an issue to worry about?

    • by skt (248449)
      LOL, quite a good post after I saw this show on THC the other day about spontaneous human combustion [alternativescience.com].. Most posts here talk about the possibility of a computer starting a real fire, but I don't actually see a post where someone has actually witnessed one.
    • by sheldon (2322)
      I've never seen a computer spontaneously combust.

      But I have seen monitors explode. Well explode is a strong word, how about a big pop and a burst of smoke?

      They were old Zenith 14" EGA monitors built back around '89 or so. We had several dozen of them in a university lab I worked in back in '92-'94 and we'd have one go every month or two. Person would just be sitting there working, and you'd hear the pop and this cloud of smoke would come out the top.

      God did that stink.. have to open the windows and air out the lab.

      But no fires that I recall... was always a bit worried about that but it never happened. We would make sure to shut the monitors off at night before leaving, just in case.

    • by Peale (9155)
      ( ) Coyboy Neal poured gasoline on it
    • Re:Poll (Score:4, Informative)

      by Technician (215283) on Thursday July 04, 2002 @07:23PM (#3824231)
      Having dealt with several failed fans in the history of being a service technician, I must say I have never seen a fire related to a fan failure. Most of the time people bring them in because of a smell and before anything shorts out. I replaced the fan and the warranty is void sticker with our shops and send it home. (now supplies are cheap so we just replace the supply except for the hard to get proprotiory junk)
      Most smoke issues seen have been:
      Ruptured filter capacitors. They have a steam rupture due to the electrolytic. (the end blowes out some times ejecting the roll of tin foil) Boiling water is not hot enough for any flames and the spacer is still wet and won't catch fire.
      Shorted power transistors. These may smoke the case of the transistor or take out some flameproof resistors before taking out the main fuse, but again no flames. Shorted disk ceramic or tantilium capitors. These are not made of flamable materials. Last is Metal Oxide Varistors (surge protectors). These tend to smoke the covering, but the part itself is made of non-flamable materials.
      In monitors, shorted high voltage supply transformer and the degausing thermistor The transformers really stink with a burning plastic and tar oder, but they are built with self extinguishing materials. The thermistors smoke the plastic covering, but the part itself is not flamable. Again, never had seen a flame continue burning after the fuse or regulated power supply removed the power.
      In summary, unless you get enough combustible lint near a severely overheated part, the risk of fire is very low.
      The only fire issues I have ever heard about were caused by some defective battery packs for a laptop. There was a massive recall for the batteries. I certanly wouldn't a flaming laptop in my lap. I may want children someday.
  • My motherboard (kt7) shuts down the computer if it gets too hot. I assumed this was a common feature on *most* new motherboards.
  • by Target Drone (546651) on Thursday July 04, 2002 @02:00PM (#3822972)
    The illustrated guide to breaking your computer [aol.com] shows you the correct and incorrect way to light your computer on fire.
  • is that there is very little risk.

    1. If the fan stops, airflow basically stops. Air contains oxygen, which is required for oxidation (!). There isn't very much air in a typical case.

    2. Fire requires fuel. If you have two ounces of dust and three ounces of flame resistant insulation in your case you don't have much of a fuel source. You aren't going to reach temperatures to cause a metal fire. Fiberglass doesn't burn.

    3. The third element of fire is heat. Paper burns at 451 degrees F. The burning point of your draperies is probably higher. Your CPU will fail, and at least temporarily stop generating heat, well below that temperature. I expect a power supply would as well.

    So, the bottom line is that you could probably contrive a set of circumstances that would produce a "PC fire," but the odds of one happening spontaneously are virtually nil. Perhaps on a similar scale with the odds of your alarm clock/radio shorting out and catching your nightstand on fire. Undeniably possible, but undeniably remote.

    -Peter
  • I know this has been done on older machines... I had a DEC AlphaStation 200 shut down due to a frozen bearing in the power supply cooling fan. Apparently it monitors the current draw of the fan and shuts down if it exceeds a certain threshold. It's not temperature, because even after cooling down it'll only turn on for about a second until you get the fan moving again.

    It's probably a good thing from a safety perspective, but it was a little annoying at the time - we lost print services for a number of printers and couldn't get the box going again until we found another fan.

  • A billion of PCs have been sold worldwide, surely there would be some statistical evidence if they were fire risks?
  • by gerardrj (207690) on Thursday July 04, 2002 @02:25PM (#3823103) Journal
    Perhaps if this has become a fear for you, then you should visit Apple [apple.com]. All of my mac systems to date run very cool. I've intentionally shut down the fans (usually one, not more than two in a case) and run the computers for hours without any significant heat build up.

    The PPC runs much cooler than its x86 cousins. Mac cases also tend to be built with convection cooling in mind with vents on back and sides unlike most solid metal cases sold for use as x86 machines. The inside of my G3 didn't start running at all warm until I installed a VooDoo5/5500 card (that thing pumps out some heat).

    I'm not looking to start a war here, but this is simply just one aspect of the Mac that most people seem to like: the cases. Many articles and revires pine over the Mac's enclosures, wishing some generic case vendor would attempt something like that for the modders on the x86 side.

    • You've never owned a 6400 or a 6500 then. The CPU/PS fans are so weak, the Mac tends to lock up on hotter days. If you look on google, you can find entire web sites devoted to publicising the problems with these machines. They were cheap, but IMHO not worth the trouble.

      And the 6400/6500 case is anything but "easy to open". You need a special tool (a case splitter) -- otherwise you have to nearly rip the calluses off your fingertips (after your fingernails go first) straining to pull the front off. When you hear the sudden, loud CRACK sound, loud enough to suspect you broke something, then you've got the front off.

      Like a lot of pre-Steve macs, the fasteners are all made of plastic or very weak metal, so unless you go carefully, you can easily break a Mac case where it will never close again properly. The PowerPC cases are great examples of the this. Everything, from the card guides for the NuBus cards to the tabs that hold the motherboard in place are made of very fragile plastic. If you're ever working inside a Mac made from about 94 to 99, be careful!

      Macs have this ridiculously undeserved reputation for having great cases that are easy to work with and won't cut you. This is pure hype. The aluminum flashing inside a Mac case as RF shielding tends to get bent up as you open and close the case and is hard to straighten. I've been working inside some PowerMac and said to myself "Hey, what's that little maroon bead on the motherboard..." before I realised I was bleeding. On the upside, the shielding is sharp enough to make a clean cut.

      SOME macs do have good cases, but most do not. Most require special tools (like torx wrenches) and a reasonable understanding of electronics, especially the Macs with built-in monitors (like not electrocuting yourself on the CRT). The recent macs once Jobs was back at the helm have much, much better cases than almost every mac that Apple ever made. If you have basic PC building skills, than a post-iMac era Apple machine should make you feel right at home. For all the earlier ones, read up on the specific model before you do anything. They're no worse to work on than cheap clone PCs, but they have their own unique gotchas that are sometimes so wierd, proprietary, and/or dumb, it's best just not to guess.

      Apple kind of runs under this idea that the computer they are selling you is actually an _appliance_, which should run reliably as designed (not that it will). But if it doesn't, you're expected to "take it to the dealer" and have them fix it, like a car or television (which nobody does, because you'll get ripped off or have to bring it back multiple times). That's the only way they're managerie of case designs make any sense, is if a trained Apple Service tech is the only one whose ever supposed to open it.

      I wouldn't buy any mac unless I already had the directions on how to open it up and work inside. That will give you an idea how many proprietary plastic parts you might have to buy from Apple for $10-$40 each if you muck around inside. If they're still available. That's what I advise people who ask me advice about what mac they should get, especially for people buying used macs.
  • by gelfling (6534) on Thursday July 04, 2002 @02:38PM (#3823169) Homepage Journal
    I've seen Watchdog cards used for this purpose. When the temp rises above X deg. it performs an orderly shutdown. I believe there are IBM desktops and servers that have this feature built in.
  • fan speed sensing (Score:3, Insightful)

    by frovingslosh (582462) on Thursday July 04, 2002 @02:38PM (#3823171)
    Many, if not all, newer motherboards have temperature sensing (a must for the Athlon chip). Some even have extra inputs available if you want to add extra temperature sensors.

    Perhaps more applicable in this case is that these boards also offer inputs for fan speed sensing when used with an appropriate fan (generally the ones with 3 wires and a small tach sensor built in). Unfortunately, I have yet to see a power supply that comes with such a fan and provides the sensor feedback to go back to the motherboard. (I'm not saying they don't make them, just in my limited experience I haven't seen any.) If you could find the right size fan with the speed sensor you should be able to install it in the power supply and route it to the MB though. If there was enough demand voiced I expect the sensor would start showing up, but manufacturers would have to know that some people we basing case purchases on this feature.

    This doesn't help older systems like this Tiger system much, but the issue has been addressed. There also have been available for quite some time temperature sensors that you installed in the case and they would sound an alarm when a critical temperature was reached. Several years ago I had a programmer build some watchdog timers for some critical systems with PIC chips and we decided to add a Dallas temperature sensor. By tapping on the reset button a few times you could get it to beep the internal case temperature back to you.(Obviously, you didn't reset the computer - the watchdog took over the MB reset input so it could reboot the system if it detected a failure. A long press of the reset could still reset the system through the PIC chip.)

    This is reasonably timely for me, just yesterday I started getting alarms that my CPU fan was erratically slowing down. So far CPU temp looks good, but I'm going to have to replace the fan (if I can find an available fan of the right size with a speed sensor) or the whole heat sink assembly. I do have another 12 volt fan with the right hole pattern, but it lacks the speed sensor and is much thicker. Maybe I could find some really long metal screws and stack both fans above the heat sink, count on the new one to cool the CPU, but the old one to help and to continue to monitor the RPM and airflow. Any thoughts?

  • I used to leave my machines on 24/7, but found that this accounted for the majority of my electric bill, not to mention sometimes needing AC, and having the disks wear out earlier. Just a thought.
  • My PS fan on my older P200 tower died when I was away and eventually the surge protectors breaker tripped. Scary thought. I have three machines at the house that currently run 24/7. After that and a few more instances of fan failure, I now actually check the fans with my hand at least once daily. My main Samba server has had two fan failures in the last two years. One I noticed because I could not telnet in anymore. The second I felt the heat when I was reaching around to check the fan. The server has only been down 3 times in two years and two of them were because of the damn PS fan. A word of advice.. If the fan starts to make noise or you notice it running slower, replace it ASAP!

  • The power supply will burn itself out before it catches anything on fire. "Dust bunnies" are highly combustible but they typically don't burn long enough, only a couple of seconds, to catch anything else on fire. The real danger with the computer is probably the power strip. Make sure you spring for a good quality, UL listed power strip. The cheap ones make poor connection with the plug and use smaller-gauge wire internally and for the cord, thus increasing the risk of fire under heavy load.

    maru
  • My dad's PC had an unfortunate accident that could have easily sent the house up in flames if it weren't for the people there at the time.

    His system was an Athlon 1.4 with SCSI, a Radeon, lots of RAM and other suitably expensive stuff (at the time), excepting the NIC. The NIC was a generic cheapo and for some unknown reason it decided to spontaneously burst into flames.

    If it wasn't for the various case fans blowing the smoke out into the house, we wouldn't have known. Luckily we got to it before the rest of the PC (and potentially the house) followed suit. The motherboard and the NIC were the only things that needed replacing, but we took the hint and replaced all our cheapo NICs with hopefully less flammable 3Coms.

    It was a lucky escape and it certainly made us think twice about leaving our boxen running 24/7, especially unattended. Flammability isn't something I usually take into consideration when buying components. Suffice to say, no more Happy Value components for me.

    Oh, and if anyone's wondering; The smell of a burning PC is very nasty. Incredibly, the OS was still alive before I cut the power. I'm also persuaded that if we had bought a cheapo case with poor ventilation, the component death toll would have been much higher. Heh.. maybe those watercooling monkeys can set up an internal sprinkler system or something. Hahah.
  • Fire Hazard Indeed! (Score:2, Interesting)

    by mr-winter (589446)
    So far I've been unlucky enough to have two systems go ablaze, and they've been fairly dust-free for most of their operating lives -- I tend to dust (and vacuum) them every month or so.

    The first was a dual-processor Pentium II board that caught fire around an inductor about a year ago. Thankfully, the case was closed and the little blaze starved itself of oxygen, and was fairly controlled. It was a small fire around the inductor, so it was going nowhere, although several nearby chips actually popped off the board. See the pictures, if you dare:

    Burnout 1 [newchibacity.com]
    Burnout 2 [newchibacity.com]
    Burnout 3 [newchibacity.com]

    Yeah, it was pretty nasty. My room was filled with smoke for a day or so, even with the window open and a fan blowing exhaust out my window.

    The second was the ATX connector on a Pentium III motherboard actually heating up to the point of melting both the connector on the board and the connector on the power supply, so all that was left was a mess of molten plastic and some bare pins. Needless to say, both the power supply and motherboard were thrown in my local dumpster.

    Anyone have similar experience? Or am I just an unlucky bastard?
  • by Peale (9155)
    A month ago I received a clients PC for repair. She claimed that it just up-and-stopped running one day.

    Being kind of doubtful, and suspecting user stupidity, I cracked it open, and found nothing wrong...supposedly. I then popped the cover off the power supply, to find some nice char.

    A bit more testing found that the motherboard would take _no_ power. I had picked up the machine from her house, so I knew the power was fine, and she was also using an excellent surge unit.

    The PC was a bottom of the line Gateway, with a no-name power supply. Not suprising.
  • P4 does it well (Score:3, Insightful)

    by txgaia (569047) on Thursday July 04, 2002 @04:31PM (#3823634)
    Toms Hardware did a test where the heat sink was removed from 4 kinds of processors while they where in heavy use. The P4 stepped down the speed until it managed a safe temp. The P3 halted and the two types of Athlons incinerated. (It hit 698 degrees almost instantly once the heat sink was removed.) Maybe the P4 is worth the extra cash. http://www.tomshardware.com/cpu/01q3/010917/index. html
  • by g4dget (579145) on Thursday July 04, 2002 @05:06PM (#3823767)
    Since [my computer] usually wide open, I don't see too much harm, but these cheap boxes that never get opened and cleaned have to be a hazard right?

    Computers are not designed or approved to be run open. It's a stupid thing to do if you are afraid of fire--they get less air circulation, they run hotter, and if they catch fire, the fire can more easily spread. Running your computer open also violates FCC rules because it will cause lots of interference, affecting radio operators, police and fire communications, baby monitors, and medical equipment.

    Computers are designed with metal cases for good reasons: they allow the fans to work, they conduct heat, they keep RF inside, and they offer some protection against fire. Don't run your computer open--it's just stupid.

  • by Yottabyte84 (217942) <yottabyte@@@softhome...net> on Thursday July 04, 2002 @05:31PM (#3823865)
    Under both Windows (Motherboard Moniter [livewiredev.com]) and linux (lm_sensors [lm-sensors.nu]) software exisits that can moniter the built in thermal and fan sensors that most modern motherboards have, and can be configured to shut down your computer when it overheats or a fan fails.
  • Honkey Crap (Score:3, Informative)

    by tarsi210 (70325) <nathan.nathanpralle@com> on Thursday July 04, 2002 @05:46PM (#3823921) Homepage Journal
    This system administrator woman is full of honkey crap in so many ways. I urge people to leave their machines on for the following reasons:
    1. Most modern systems are made to "sleep" when you're not using them. If your monitor is set to power off, your hard drive to spin down, you'll be fine. Power consumption at a low, automatically.
    2. Every hard drive that I've seen fail sans one or two have failed when the machine got turned OFF. The next time you turn it on...nothing. Rarely have I seen a harddrive fail while the machine is powered up.
    3. The power surge that flows across the motherboard at powerup, not to say anything about the repeated heat-cool-heat-cool that the chips go through as you power on and off each day cannot be good for them.
    4. Dust does accumulate, but not THAT fast. I just powered down a 279 day uptime server and the dust was there, time for a cleaning, but nothing significant. (2 fans - 1 PSU and 1 CPU)
    5. Security by shutting computers off isn't security, I don't care who you say you are. Educate your users.

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