Just fixed my 60PX950 which had a no picture problem. Power supply tested ok, so I ran the self test by disconnecting the main board from the ASIC/3DF board and jumpering two terminals. Self test ran ok, so it was a bad main board.
All the instructions I've seen online suggest baking the entire board at 385F for 10 min but that seemed like overkill to me. There's only one chip on the mainboard that is BGA soldered and that is the main processor beneath the heatsink. Took off the heatsink, applied some flux to the processor, then heated it up with a heat gun to 200C for a few seconds. Voila, that worked! For extra safety I also decided to make a cutout on the rear panel to install a small fan which I am powering off the 5V from the power supply. Hope this fix holds!