Laptop Fan and Overheating - Cleaning Fans and Troubleshooting Hot CPU Failure

Copyright 2010 by Morris Rosenthal -All Rights Reserved contact info

Order book for $24.95 or printable ebook for $13.95

The Laptop Repair Workbook

Laptop Deals

Computer Repair with Diagnostic Flowcharts

Questions? Comments?

Copyright 2010 by Morris Rosenthal

All Rights Reserved

removing the plastic shield over the laptop keyboard Many of us own laptops where the fan seems to run an annoying amount of the time, but it's better than a laptop fan that doesn 't run at all. When the fan in your notebook fails, the usual symptom is an overheating CPU and automatic shutdown. Sometimes the laptop runs for 10 minutes, sometimes for a half hour, it depends on the task and the power. Troubleshooting a hot CPU can be as simple as making sure you aren't blocking the airflow outside the laptop. Often times, you can access the fans and heatsink without a huge job, on this Toshiba A65, all it takes is some careful prying and two screws. As always, remove the battery before working on any laptop. The first step is removing the combination blank and hinge cover that allows access to the two screws securing the keyboard. It is snapped into place with little tabs on the long edge and a big tab on each end.
The picture to the right shows how the blank and the hinge cover are all one piece of plastic, so you have to open the screen to fully remove the blank. I should mention for desperate people with no mechanical skills, one non-invasive way to extend the length of time a notebook with poor cooling will run between shutdowns is to run it on battery and choose the most aggressive (ie, longest life) power saving mode. BTW, I'm working on this notebook because I was asked to bypass the power connector as a favor. However, the owner's got five kids in the house and I burned my finger on the metal part of the 100BaseT port after I got it charging again, so I'm afraid to return it for safety reasons. freeing the plastic over the laptop hinge
removing the laptop keyboard to access the motherboard The problem I was originally asked to fix should have tipped me off to the overheating issues this notebook would suffer. The pin had broken out of the center of the power connector on the motherboard, which meant the battery couldn't be charged. My fix (really a kludge) was to solder a new wire directly to the connector and bring it out the I/O port blank on the back of the notebook. The coax power cable was HUGE. Turned out to be rated for 2.0 amps. Two screws secure the keyboard in the laptop, and it's not even necessary to disconnect the ribbon connector from the motherboard to access the fans. This Toshiba laptop uses two fans, a large exhaust fan that pulls cooling air through the body of the notebook, and a smaller CPU fan on top of the large heatsink.
The large fan to the right draws cooling air in the bottom of the laptop, the smaller fan in the center is directly cooling the CPU. Troubleshooting overheating is pretty much limited to making sure the laptop fans operate and aren't completely burried in lint. This is a pretty robust cooling system and likely to keep most laptops from shutting down from thermal overload protection, but they stuck a P4 2.8 Ghz CPU in this puppy! When I went out on the web and read some reviews of how this laptop performed when new, I saw comments like "Keyboard gets too hot to type" and "Frequent shutdowns from overheating." Sony made a Vaio with the same CPU, HP made an Pavilion and Dell an Inspiron. I've seen similar overheating and battery life complaints for them as well. laptop motherboard with fans and heatsinks
dust build-up on fan and heatsink As you can see to the left, there was a build-up of dust on the CPU fan which I blew out with compressed air, but not enough to cause any thermal shutdown issues. The reason I burned my finger on this boat anchor is it just runs too hot as a design flaw. OK, I didn't get a blister, but I'm afraid to put this laptop with a kludged power connector in a family home. I really don't know how they could have forced more air through this thing than with the big intake fan they are already using, so troubleshooting includes making sure you have unobstructed airflow to the BOTTOM of the laptop for the fan to function. If you run the thing on a bed, or on your lap with the fan grille blocked by your leg, it's going to cook for sure!
Before taking it apart, try the troubleshooting flowchart for overheating exhaust fan inside laptop
The printable eBook version of The Laptop Repair Workbook is now available for download anywhere in the world.