It means some part is heat sensitive (yes, it does not mean it is overheating but the part likes to be warm.)
As you are a TV Tech you would inspect all boards for the BAD CAPS plague and hope you find that. Then you use the service manual and its diagnostic tree to see what board to replace first.
My TV displays a predominantly green screen at switch on. Shapes can be seen through it. After about 5 minutes it clears and all is watchable. I've tried increasing and decreasing all the picture settings (colour, brightness, contrast, backlight etc) but nothings appears to affect it. I've taken a photo of it which I can send to anybody if they think they may know what the problem is.