@vistalu motherboards from two separate places with the same error, is possible but unlikely. The white screen is just your backlight turning on and really does not give you an overall idea about the display. I'd check the ribbon cable. check for tears and nicks etc. OF course, you have checked this guide [guide|20229|How to fix the PSP E1000 psp e1000 WHITE SCREEN - iFixit Repair Guide|new_window=true] as well. If none of this works, try a new display as well.