Sarasota PC Monitor
Tech Talk(10/99)
It's the heat!
by Brian K. Lewis, Ph.D.*
Member of the Sarasota Personal Computer Users Group, Inc.Yes, I know that Florida in the summer time is rather warm, but that's not really what I had in mind. I was thinking how hot is your computer and its components? In general, if you are comfortable in your work area, then so is your computer. However, there are exceptions to this. So the question becomes, how hot is the interior of the case where your CPU, motherboard and hard drives are working? It is very important that these components be kept at a comfortable working temperature. I know of one instance where a computer was shipped with other household goods. When it arrived, it didn't work. The heat it had been subjected to had destroyed the CPU and several auxiliary chips. Luckily, they were all socketed and not soldered to the motherboard. That simplified their replacement. So how do we keep these systems cool?
Every personal computer has at least one fan, the one included with your power supply. This fan usually blows air out of the computer case. If you can get your hand to the back of the case, you can feel a light stream of air. If there is no air movement, place your hand on the metal at the back of the case. If it's hot, you may have a real problem in the making.
Case in point: I received a call about a customer having problems with a CD-ROM drive. It was apparently not running most of the time when a CD was placed in it. Since, the drive was under warranty I swapped it out with a new drive. Everything seemed to be fine. Two weeks later, the same customer said he was having sector failures on his hard drive. Scandisk was reporting an increasing number of bad sectors. So, I figured I would run a diagnostic program to verify the problem and swap out the hard drive.
When I arrived at the customer's location and started to move the computer, the back of the case was so hot I couldn't keep my hand on it. I moved the case into the open, turned the power on and checked the cooling fan. It was inoperative. So, in this case, a failing power supply cooling fan had caused the loss of the CD-ROM and the hard drive. The lack of a cooling fan allowed the temperatures inside the case to rise high enough to damage the electronics in both drives.
In most Pentium class computers, there is an additional fan attached to the central processor, the CPU. This fan and its heat sink are very necessary to keep the CPU from overheating. You have to realize that the electrical pathways inside the CPU are much finer than a human hair. Consequently, it doesn't take a large temperature increase to disrupt these pathways.
Another example was an Intel 133MHz system that shut down spontaneously while in use.
It happened several times while the customer was working in an accounting program. In this case, the power supply fan was working perfectly. When I opened the case, I found the CPU fan dangling from its electrical wiring. It was no longer attached to the CPU. Luckily, that problem was caught soon enough that there was no permanent damage to the CPU. All it took was a new fan. However, the heat was sufficient to have warped the plastic connectors that attached the old fan to the CPU.
Another heat problem occurred in a new Intel Celeron 366MHz system. I had tested this system by running it for several days on a tabletop. In that situation, there was nothing to obstruct a free flow of air into and out of the case. The customer's installation was slightly different. He had the case located under a desk with the back of the computer very close to a privacy panel. He started having failures in which the system would shut itself down without warning. In this case, the computer motherboard had temperature sensing that could be read in the BIOS setup program. When I checked it, the interior temperature was more than 105 degrees, which is too high. I replaced the CPU fan with a higher speed fan and the operating temperature dropped to 94 degrees. Since then, there have been no unexpected failures of the system.
Another cause for overheating problems in a computer is dust. When was the last time you cleaned the fan louvers on the back of your case or the vents on the front? If you are like most users, the answer is never. Just consider that a computer case that sits on the floor has a fan blowing air out at the top of the case. That means air must be entering from somewhere to keep the air moving. That somewhere is usually on the front of the case near the bottom. I am sometimes amazed at the amount of dust that can accumulate inside a computer case just from this airflow. So why is dust a problem? Simply because it acts as an insulator. The accumulation of dust on the motherboard, on drives, around the CPU and heat sink will block the heat exchange process. The heat is retained by the components instead of being transferred to the air stream. You should consider cleaning out the inside of the case on a regular schedule. The frequency of the cleaning depends on the general environment around your computer. A regular monthly cleaning should help keep the system dust-free.
As can be seen from these examples, it is important to keep your system temperature cool enough to prevent drive and CPU failures. So you should periodically check your power supply fan to be certain it is running. It also wouldn't hurt to open the case and check on the CPU fan. Do that every time you clean out the accumulated dust. Certainly a cool computer helps maintain the computer users "cool".
*Dr. Lewis, a former university & medical school professor, is a computer consultant doing instruction, hardware/software services and system upgrades.
He is available to help you with your home or business computer problems. He does make house calls and can be reached via e-mail at bklew@worldnet.att.net or voice mail at 941/925-3047. :
Copyright 1999. This article is from the October 1999 issue of the Sarasota PC Monitor, the official monthly publication of the Sarasota Personal Computer Users Group, Inc., P.O. Box 15889, Sarasota, FL 34277-1889. Permission to reprint is granted only to other non-profit computer user groups, provided proper credit is given to the author and our publication. We would appreciate receiving a copy of the publication the reprint appears in, please send to above address, Attn: Editor. For further information about our group, email: admin@spcug.org/ Web: http://www.spcug.org/
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