Yes I know this issue well. We have had about 15 boards so far go bad. The problem on the board (after talking to an engineer at Panasonic repair) is that there is a fuse that is underrated and various load imbalances such as small surges, ringing all phones simultaneously or a heavier power draw causes the fuse to pop. It is an on board fuse and cannot be popped out. It has to be sent back in so that a new one can be soldered on. All cards that have Version 3.0 firmware on them when you unbox them and plug them in are the new fuse version and are fine. Anything else is just a guessing game to wait and see.
