Probably ground issues. When you have two seperate power supplies (the PC supply and the wall adaptor) with circuitry inbetween you are going to run into the possibility of voltage potentials between the ground lines. Is everything soldered well between the two? Are both power supplies properly grounded (if they have ground pins) in the same outlet or power strip? Two fun problems to ponder: 1. If the wiring between the two devices is not excellent (say you twisted the wires together and taped them instead of soldering) then an intermittent ground can develop, and when the ground is floating a potential can develop that will bridge the ground gap, cause a burst of current, and fry all sorts of things. 2. If the ground pin is missing on any plugs, or the ground wiring between the outlet and the cricuit breaker box is broken/corroded/etc then the ground of the computer may float hundreds of volts above 'real' local ground. Given the right circumstances this will damage circuitry and people. (example: A highschool teacher would generally clip off the ground pin for A/V carts. With the plug turned around backwards, they would connect to the building's coax, which had poor grounding. Another teacher would receive a zap from the ground of the coax when they attempted to connect their TV) Isolation is one way to fix this. Powering both circuits from the same supply is another way (use the USB port power). These should be first on your list to try. Good luck! -Adam On Wed, Dec 31, 2008 at 12:15 AM, solarwind wrote: > I swear I don't know how this happened, but today one of those > "bubble" ICs on my HD44780 LCD quite literally "popped" and filled my > room with the foul smell of burnt semiconductor. Now my LCD module is > rendered to be pretty much useless. How could this have happened? It > was connected to my parallel port, happily displaying stuff and this > incident happened spontaneously. I did nothing... > > -- > solarwind > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- Please rate and vote for my contest entry: http://mypic32.com/web/guest/profiles?profileID=50331 -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist