Acer A715-42G working bios.bin GH5VZ LA-K831P rev:1.0 working bios bin Acer A715-42G boardview GH5VZ LA-K831P REV:1.0 boardview LA-K831P BoardView.bdv GH5VZ LA-K831P schematic PDF.pdf Acer Aspire A715-42G schematic