Preliminary judgment is a memory card interface circuit board problem. Then open the camera's rear panel, and then remove all cables blocking the motherboard and LCD viewfinder screen, exposing the roots of the memory card slot on the motherboard. Carefully check the socket pins, three pins found desoldering. Carefully welded with electric iron desoldering tip of the pin, and there is no confirmation weld short circuit, put the machine back in the same. Boot troubleshooting.maRservice manual download site