The motherboard circuit routes graphics to the HDMI port independently of the lcd cable and the lcd itself. The part that controls graphics is embedded inside the CPU. So it looks like the problem is more serious than just connections. Though I guess it doesn't hurt to try anything at this point. For the GPU to fail without any kind of physical impact is really new to me. But what do I know?
XDA Developers was founded by developers, for developers. It is now a valuable resource for people who want to make the most of their mobile devices, from customizing the look and feel to adding new functionality. Are you a developer?