Fan Always Runs Or Laptop Overheats And Shuts Itself OffCopyright 2008 by Morris Rosenthal -All Rights Reserved contact info |
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The printable eBook version of The Laptop Repair Workbook is
now available
for download for $13.95 anywhere in the world.
Warning! Before Disassembling Laptop always remove battery. This draft troubleshooting procedure is intended for people who know what they are doing around electricity. It's offered "as is", not as professional advice. |
Note that these steps correspond with decision points on the flowchart and are reached directly by clicking on the diamond symbols. The text below cannot be read sequentially.
Smoke or burning odor? Never play with fire. If you see smoke or smell a burning odor, it's not something you can afford to ignore. In some instances, brand new laptops will give off a bit of odor when they are first powered on that smells a little like hot plastic and a little like the ocean. In any other situation, smoke or smells coming from your laptop are not normal. If you recently spilled something on the laptop (shut down immediately) and have already dried it out and cleaned it to the best of your ability (or your repair person's ability), there may be a little residual burning off the first time you run the laptop and get it up to operating temperature.
High air temp or sun? All laptops will overheat if you use them in a cruel enough environment. Obvious examples are stifling hot attics, vehicles without air conditioning in the summer and placed on hot surfaces. Hot surfaces aren't limited to radiators or desks touching steam pipes, they also include dark surfaces the get a lot of direct sunlight, even if they are located indoors. Using a laptop outside in direct sunlight in the summer is more than a problem for your eyes, it's also likely to lead to overheating. Notebook computers are entirely reliant on air flow for cooling, and the higher the ambient air temperature, the less the laptop will be able to cool itself.
Is battery too hot? Some people are more sensitive to temperature than others, so using "too hot to touch" isn't a great troubleshooting technique. Unfortunately, very few people have a thermometer around capable of measuring temperatures through the normal operation range of a battery, including most computer technicians, so touch is all most people will have to go on. If the battery seems excessively hot, first shut down, check the web to see if it's been included in a recall or if a hot battery is typical of the the particular laptop model. Then proceed to the battery troubleshooting flowchart.
Fan never runs? Most laptop users are accustomed to hearing the cooling fan(s) straining away during certain intensive computing operations, and even the quietest, best behaved notebooks normally run the fan at low RPMs during normal operation. If the fan never runs, it doesn't mean your laptop is overheating, but it does mean that something may be wrong with the fan or the settings. If something is wrong with the fan or the temperature controller, eventually the laptop will overheat, unless you do all of your work in a walk in freezer.
Recent upgrade of BIOS? Anecdotally speaking, it seems that "my fan never comes on anymore" problems often occur after a BIOS upgrade. Manufacturers generally encourage users to install the latest BIOS version available for the model on the manufacturer's website, and if you call tech support with an in-warranty fan or overheating problem, the first thing they are likely to do is tell you to upgrade to the latest BIOS. The problem is, the notebook really should operate normally with the BIOS version you purchased it with, or they shouldn't have sold it to you. If you want to add new peripherals or upgrade an internal component and it's not supported unless you upgrade the BIOS, you don't have much choice. Outside of that, I avoid BIOS upgrades like the plague, keeping in mind that a failed upgrade can leave you with a paperweight that can only be repaired by sending it out. If the fan problem appeared after you upgraded the BIOS and the laptop which was operating fine originally is now overheating, I'd try reinstalling the original BIOS if available.
Cool settings BIOS and OS? - There's no universal standard for what BIOS settings are user adjustable for a given brand or model of laptop. If you can lower the temperature at with the fan automatically powers up and you're having overheating problems, it can't hurt to do so, though you should also try the less invasive cleaning techniques given at the end of this flowchart. There are a large number of OS (Operating System) settings that affect the amount of heat the laptop will generate, from the speed of the processor and the brightness of the screen to the efficiency of the cooling system. The manufacturers try to give the user as much control as possible, but if you or another user ran the cooling control down to the minimum to reduce fan noise or extend battery life, it may be time to compromise.
On the other hand, if the settings are all on the defaults, the fan never comes on, and the system is overheating, it's either a fan failure or a problem with the control circuit. The fan itself is a replaceable DC fan that usually can be replaced without removing the heatsink (if it's mounted directly on the CPU or graphics processor). One simple test for notebook fans is to blow on them. If the fan doesn't spin, either the bearing has failed or something is melted or jammed, because the motors are tiny. Testing the control circuit is an open-unit bench job that I don't recommend unless you are an experienced technician. It's easier to just replace the fan with a known good unit, and if it still doesn't work the problem is in the controller or the power supply to the fan.
Laptop on hard, flat surface? I have to believe that the leading cause of laptop overheating is what engineers call "poor siting". Notebook computers are designed to run on flat level surfaces, with at least a couple inches of unobstructed space all around. Running a laptop computer sitting in the opened shoulder bag on your lap is a great way to block intake and exhaust vents and overheat the poor computer. Running on a bed is equally bad for laptops that have vents on the bottom, and if it's a soft bed or there are loose sheets and blankets, the side vents can get blocked as well. Running on your lap is generally discouraged or forbidden by manufacturers. But many of us do at times anyway, and it's important not to block air vents on the bottom, which may be impossible on some models. If you're troubleshooting an intermittent laptop overheating problem, the first check is to pick a nice cool place with a large flat surface to run the notebook and see if the problem stays away. Keep in mind that the laptop automatically shuts off to protect itself (and your investment), not to be a nusiance.
Laptop shuts down? Computers may not be smarter than people, but if they're designed properly, they will shut themselves down before overheating to the extent that they do themselves damage. If the smart person keeps turning the notebook back on and figures out a way to foil the protection, the laptop is probably doomed. Once a laptop shuts down for thermal event protection, it may refuse to power back up for a fixed period of time, five or ten minutes, or it may begin to boot and shut down immediately as soon as it boots to the point that it can figure out that its too hot. The over-temperature protection is generally a BIOS rather than an operating system function, so one sign of an overheated laptop is one that shuts itself down while you're using it and then refuses to boot as far as the operating system unless you leave it alone for an hour or so to cool down. Unless you've been working in a very unfriendly environment, high temperatures, direct sunlight, etc, you should take even a single overheating shutdown as a warning to back up your data at the first opportunity and to give the cooling system a serious cleaning.
Hot spot, fan always runs? Many laptop brands and models have characteristic hot spots, like a particular corner of the keyboard or over the battery compartment. Before proceeding with the more invasive cleaning techniques that involve opening up the laptop (and potentially breaking something), spend some time searching the web for user feedback on your make and model. The bothersome hot spot on your laptop that none of your friends or colleagues have ever hear of may be a characteristic issue with your particular model and not worth a major panic.Similarly, if the fan always runs, or almost always runs, it may be a characteristic of the particular model that it simply gets hot in normal operation, or the fan control software might be poorly conceived. As long as the laptop isn't overheating, I'd probably learn to live with a fan that seems to run too much if it's typical for the model, and only get worried when I don't hear it anymore.
Data loss, lockups? Troubleshooting all of the software problems that can cause data loss, bring on a blue screen of death or a frozen process is beyond the scope of page sized flowcharts. Overheating of the CPU, the RAM or the heard drive can cause data corruption and lead to the laptop locking up, but overheating is only one of many potential culprits. If you aren't having any performance related problems, it's possible that your laptop isn't overheating at all (or you took a wrong turn on the flowchart), so you might start over at the top or try another flowchart that more closely matches the symptoms of the problem the notebook is experiencing.
Same problem low temperature? If you wait until the laptop is completely cooled down (overnight), use it in a friendly temperature environment and the errors you are seeing still occur as soon as you boot, odds are if the problem is related to overheating, the damage is already done and you now have a hardware failure problem. Checking the other flowchart for motherboard, CPU and RAM troubleshooting may narrow down the problem. If the problems don't immediately come back when the laptop is first booted cold, but only appear once it heats up, it's possible that a thorough cleaning and inspection will help clear up the problem causing the overheating, and no hardware replacement will be necessary.
Low battery, boot order? The default setting for most laptops when they reach a critically low battery state is to go into hibernation, the quickest way they can save any data in open applications and drop into a low power state until the AC adapter is connected. If the battery has failed and won't accept a charge, if there's a problem with the AC adapter, or if the operating system software isn't as clever as it should be, the system may get locked into a loop where as soon as the operating system boots to the point it can identify a battery problem, it goes back into hibernation waiting for salvation. I've even heard of instances of laptops continuing this behavior with the battery removed! If the battery and AC adapter are good, the slow fix is to let it charge for a while before trying to boot. If that doesn't work, try changing the boot order in the BIOS to the CD/DVD, just to break the loop.
Cleaning process. Do the simple things first. Close the laptop lid, unplug all cords, inspect all four edges and the bottom of the laptop for air vents to familiarize yourself with where they are. If you spot air vents on the bottom about where you are accustomed to holding it on your thighs, that's probably the whole problem right there. Likewise, some people misunderstand the concept of creating more air clearance under the laptop and try jacking it in the air an inch with a book! The most common troubleshooting solution to notebooks overheating is simply operating them on a hard flat surface with unimpeded air flow all around.
As you look into the vents, you may see dust build-up on foil radiators or heatsinks, not to mention on the fan assembly if it is visible. Depending the the size of the vents, you may be able to loosen up and capture some of the dust with Q-tips (cotton swabs) and suck it out with an electronics vacuum, but most technicians head straight for the compressed air. I'm not a huge fan of using compressed air to clean laptops without taking them apart, because while you'll definitely blow the dust off whatever you aim at, you'll often be blowing it somewhere else in the notebook. The immediate result will be a cooler running notebook because dust and lint build-up on heatsinks can act as a blanket, keeping the heat from being radiated and convected away, but if all you've accomplished if throwing that blanket over some other hot components that aren't visible through the vents, you may have greater problems in the future. Make sure you use a canned compressed air sold for cleaning electronics, otherwise there may be harmful propellants or liquids mixed in. Read the instructions, and if they tell you to always hold the can upside up, be careful to obey, because holding it upside down may result in squirting liquid.
Before opening up the laptop, find the owners manual or search the web for exact instructions. Once you gain access to the active cooling components, fans and heatsinks, you can blow off all the dust with compressed air and get most of it out of the case. Some fans may be damaged if you spin them up beyond their operating RPMs with the compressed air, so you should prevent the fan from spinning if blasting it up close. Pay careful attention to the air paths in the laptop and look for any blockages, both when you open it up and when you go to put it back together. Notebooks are generally engineered with very little slack in the cables to keep them from flopping around and potentially breaking up the airflow, but something as innocuous as a loose paper label flipping up and blocking an air path can cause a world of trouble.
In severe cases of laptop overheating, especially those where data corruption or automatic shutdowns are occurring, you should check that the active heatsink(s) are properly installed. The only way to do this is to remove them. Depending on the design of the laptop, you may have active heatsinks on both the CPU and the video processor, and there may be some passive heatsinks with fans strategically located to circulate air over them. Some passive heatsinks are basically glued to the package so you don't want to mess with them if you can avoid it. The active heatsinks are mounted with a latching mechanism and can be removed, though they might stick pretty fiercely to the processor depending on the condition of the existing thermal paste.
When you purchase the new thermal paste, it may be sold in a kit with a thermal paste cleaner. I'd recommend trying it since cleaning up the old goo is just as important as applying the new goo properly. Don't use household cleansers to clean up thermal paste, they can leave an oily residue that actually prevents heat from conducting to the active heatsink, worse than nothing. If you don't purchase a cleaning kit, the fallback is scraping with a credit card and cleaning with isopropyl (rubbing) alcohol on a clean cloth or paper towel, which is what I do. Once the new paste is applied and you've reinstalled the active heatsink and closed up the case, there's no guarantee that your overheating problem will be solved. Overheating may be a symptom of chip level degradation and imminent failure. While poor cooling was likely a contributing factor, closing the barn door after the cow's gone isn't going to undo the damage.
AC adapter in use? If you see a puff of smoke or smell a burning odor and the AD adapter is in use, you should unplug it immediately if you can. I've burnt my fingers on short circuited wires more than once, so exercise extreme caution. When there's a risk of fire, as documented in laptops with defective batteries, your first priority should be guarding against an outbreak of fire, not worrying about the laptop condition or studying this flowchart. Some people will immediately call the fire department or grab the fire extinguisher at the first sign of smoke in electronics, I'm more of a "move it outside" type, but again, I've been burned doing it. If there are flames coming out of the laptop, it's history, so the fire extinguisher or fire department are the way to go. If it's just the odor of smoke, unplugging the AC may preserve a laptop that can be reasonably repaired.
Troubleshooting the cause of the smoke, unless you just poured your coffee on the keyboard, requires taking the laptop apart and visually inspecting the components down to the board level. If the laptop at all hot, wait for it to cool before attempting dissembly. Always remove the battery pack before opening up a laptop. Since component spacing in laptops is so tight, you'll rarely get lucky enough to zero in on the problem with your sense of smell, which is sometimes effective with larger desktop computer components. Inspect the circuit boards, connectors, remove and inspect the drives. Pay special attention to electrolytic capacitors and discrete power semiconductors, usually located very near the power input. If you find a burnt spot or signs of melting on a discrete component, such as a hard drive, dvd drive, capacitor or power semiconductor, there's a reasonable chance that the failure was internal to that component and that replacing it will fix the problem. If there's a large burnt or melted spot on the main circuit board, the notebook is probably toast, it's rarely cost effective to even attempt a replacement.
If the problem was a hot plastic odor and you can't find any signs of damage during your visual inspection, it's possible that the laptop was overheating and you caught it in time. Some people are more sensitive than others to plastic odors, and there is always the possibility that a little foreign matter, food or insect, found it's way into the notebook and got incinerated. Read over the procedures for troubleshooting laptop overheating, as if you never encountered the burnt odor, to make sure the notebook wasn't operated in such a way that it was being encouraged to overheat, check the fans and the vents.
The printable eBook version of The Laptop Repair Workbook is now available for download for $13.95 anywhere in the world.
