Hi, I have a iPad2 wifi 3G model. The glass was broken and must have damaged the cable, because there is no touch in the touch screen. I would like to power it down to replace the glass. Or as an alternative know the consequences of unplugging the digitizer cable and the LCD screen with power applied. Is there a hard non-destructive shut down one of these things? Or as I mentioned above, any experience with working on one without shutting down first?