While official direct links are often restricted to authorized service centers, you can find the software on dedicated technician forums and community megapacks:
While holding the button, plug the TV back into the power outlet. Download RT2851P839 3840x2160 AKAI USB part10 rar
Press and hold the button on the TV chassis (or sometimes the OK button on the remote). While official direct links are often restricted to
For hardware troubleshooting beyond software, you can access the HK.T.RT2851P839 Maintenance Manual on Scribd, which includes schematic diagrams and quick repair steps for common power and display issues. Download RT2851P839 3840x2160 AKAI USB part10 rar