Slashdot Mirror
Is Your Computer a Fire Hazard Waiting to Happen?
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.
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!
If you could be told what you can see or read, then it follows that you could be told what to say or think - BoC
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.
-- "Other than that, how was the play Mrs. Lincoln?"
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.
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?