is arudino frying my usb ports?


I've been using the aruduino duemilanove on my mac book pro and then after a few days my usb ports stopped working. I had been using a external power source with the arduino: an AC adapter input:120VAC /Ouput12VDC

I changed computers. I used a friends macbook and then after a day I had the same problem. the usb ports stopped working. I reinstalled my computer and reset the PRAM everything else I read about on the mac forum about the usb ports. Nothing...

Could the AC power have fried my usb ports??

Well, if it's a Duemilanove, it has a 500ma fuse on board to protect your USB ports. It's resettable as well, so once it pops, it generally starts working correctly again after just a short time.

But if you have AC-input and DC-output, you're not working with AC voltages at all. (Unless you've cut the wire closer to the wall.)

But one thing I'm curious about.. did you have the power supply plugged in while you had the USB drive plugged in?

The board will automatically choose between the two power supplies.. whichever is higher, but I've heard that trying to use both at the same time has caused peoples boards to warm up more than normal. (of course this is expected with a 12v supply)

I'm not familiar with Macs, but I can't say I've ever ran into this problem. (But I haven't used two supplies at once either, so could be a contributing factor)