My original Acer Iconia A500's AC charger's wire tore at the ac plug box and, although back together and charging for now, it's just a matter of time til it becomes unrepairable. I've received an aftermarket 12v charger that claimed to be for the Acer A500 (among other's) but it wouldn't charge. It seemed to fit good and the battery symbol in the lower right of the screen showed that it was being charged but the power switch would light as a blinking red rather than a solidly lit red as it does normally when charging and it did not charge. Reading various forums and also reviews of chargers it seems the same chargers will work for some A500s but not others. Does anyone (hopefully any Acer techs lurking here) know the actual dimensions of the charging port and if it's varied through the years? It seems it's the center pin that varies, at least from what I've gathered from all the comments. Thanks in advance, Bud