Dots are twinkling.
Do you detect dots on some part of the display or they are flickering?
How to fix
1. If picture test or USB function is available, try the function and check if the same symptom appears on the same location again.
2. If the symptom is detected only when set-top box or external device is connected, check the device.
3. If the symptom is detected only at certain channel or program, this might be caused by the condition of production, sending condition of the broadcasting station.