No Video on Philips 50PF7321D Plasma TV. This TV turns on and there is sound. However there is no

Question

This TV turns on and there is sound. However there is no video on the screen. This problem happened suddenly and did not show any signs that it was going to happen. Thought that maybe it was a power module problem but checked all of the voltages listed on the Power PCB itself and they are all present and within listed ranges. How does my workshop tech check the PDP itself? Any Service Manuals available for this TV?