Thanks I removed led bank fortunately I had had a power supply big enough to power up the bank 96v but bank will light up at 76v found group that did not go. reduced voltage to12v tested led in pairs found one with a dry solder joint resoldered tv is now working fine it was not the board after all,you learn by trying things. I created a new problem when I installed the new A board it asked me if l would like to upgrade the software to 4.735 thinking it would be a good idea and found out that it wipes certain apps principally YouTube and google it seem the only way to fix this is to buy ie a CromeCast and then use an external device to use the tv don't you love modern technology! Does anyone know another way around this problem.