Panasonic TX P50X50B red led flashes 14 times

[RNRepair]

Hi, hope someone can help me with this. Customer watching through USB stick then suddenly heard crackling, the screen went blank, and set stops responding to the remote. Now the set tries to come on but then red LED blinks 14 times. Very similar to this post:
http://www.tv.quuq.org/forum/index.php?topic=7463

Another thread mentioning 14 red blinks
http://www.tv.quuq.org/forum/index.php?topic=6737

Following the advice on the above threads, I've just replaced the A-Board (TNPH1002-1-A).
But there's no change: red LED blinks 14 times.

Any help is very much appreciated.