after having plugged the power-adapter with inverted supplies (19.2V +/- swapped) into the ASUS U5F notebook of my wife (you'll understand the severity of the problem), it has burnt a little bit and since then the USB (maybe the 5V supply) seems to not work correctly anymore (the rest seems to be ok).

To investigate the problem until now I found out the following:

 - the schematics of the mainboard are not available
 - the device seems similar to the Asus U5A (no schematics available either)
 - at least one component has burnt (as pictured below)
 - I'm unable to identify what this component is doing exactly, so I can't replace it
 - the components is of probably packaged using "SOT-223-4"
 - the marking code is 8C609 (I could read it before cleaning the section, now there is only "8C6" left)
 - I suppose it is a LDO-regulator, but I don't know the exact reference


[Picture of the full motherboard (could not upload here, so just a link)][1]

[Picture of the section of the motherboard showing the section where the component is located][2]

Thanks a lot for your help in advance.


  [1]: http://www.wi-bw.tfh-wildau.de/~pboettch/full.jpg
  [2]: http://www.wi-bw.tfh-wildau.de/~pboettch/zoom.jpg