Reinstalling the TVs original firmware can rectify many issues.
Please follow the steps below to download and install this on your TV:
1. Download the firmware upgrade by right-clicking on the link below and selecting 'Save link as...' or 'Save target as...':
KALED55KU8000SZA Firmware File.
2. Copy or Save the "MstarUpgrade.bin" file onto an empty USB stick. Please ensure that your USB stick has no other files on it and is 16GB or smaller in size.
3. Please unplug the power adapter from the rear of your TV and confirm that the standby light on the front of the TV has turned off.
4. Insert the USB stick into the TV and reconnect the power adapter.
5. Continuously press the power on button on the TV until a blue screen appears. It should now be installing the firmware.
6. The TV will restart automatically once it has finished installing.