Re: Samsung UN55KU6300FXZA

If everything on the PSU is checking out OK. Then I'd start looking at the mainboard. There are often times when the EEPROM gets corrupted and needs replacing. The EEPROM is where read-only firmware is held. I've attached an image of a common Samsung EEPROM IC. See if shopjimmy sells replacements and solder it in.

Hope this helps!...