just curious but would a power board from a 43" or 50" of the same tv range work i.e 43rp620k, 50rp620k?

I did buy one in the hope it would but backlights just flash on and off as soon as power is applied. I guessed it only for 43 or 50" with fewer leds to run i.e 40" 21 leds, 50" 26 leds rather than 55" with 30 leds.
With the leds disconnected the tv turns on and operates fine.

Though it was sold and advertised for 43, 50 or 55".

Perhaps just needs repairing properly as the only replacement on the board is the led...

Been running the tv with backlight at 45% for a good few minutes more than it lasted before so fingers crossed. Shall increase the backlight once happy its ok at 45%.

I did also check the blue ceramic caps beforehand and all seemed good.

ok so have now changed all 3 - diode, mosfet and led driver i.c, the diode and led driver i.c seem to be ok comparing readings out of circuit to new components so just the mosfet blown this time.

thanks, shall try replacing all 3 at once as I have more spares.

How do you test the blue ceramic caps?