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| Ram Krishnan says he felt the need for a few chill pills himself when the Targus USB-powered laptop cooler (wiring shown here) he bought to keep his IBM Thinkpad T40 (which he says can get really hot) from overheating stopped working after a month. Think a really big, really expensive trivet.
So what's an engineer to do but get his multimeter out and investigate? |
"When I opened the cooling pad, I could not find anything wrong. The wires seemed to be ok. So I used the multimeter to look at the voltage at the power jack that connects the USB cable to the pad. There was no voltage. Then I opened the plastic casing of the small switch in the cable. That's the switch you see in this image As you can see, the wires and the switch are really flimsy. There is no short circuit protection either.
One of the wires coming into the switch had broken off. I touched the wire to the switch lead and the fans started spinning.
The product clearly failed because of an open circuit. View schematic.
At $24.99, this "cooling mat" is nothing more than an overpriced trivet! And though I am not a hardware guy, I think the cooler should have some kind of short circuit protection to protect the USB hardware in the laptop."
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Comments (1)
too bad this "techie" doesn't know that the USB type "A" ports are all internally protected and do not require protection on the user devices plugged into them
Posted by jimmy | December 14, 2007 2:38 PM