@rayj58 you are not providing us with enough information. We do need to at least know what model your TV is. You want to start by checking if the red power LED on the front of the TV and see if it is flashing. If it does, we need to know how many times before it pauses and flashes all over again.
First thing you want to try is to reset your TV. Unplug the TV for a few minutes, then plug it back in. Sometimes this clears any issue. If it does not work you will most likely have to remove the back of your TV and take a look at the boards. Post images of those with your question. That will allow us to see what you see. Use [guide|21499|this guide] for that. The list of possible failures includes the power supply, the main board, the scan drive or sustain boards, T-Con board and of course the panel itself. Once we know what models your TV is and if it generates an error code we can probably narrow this down.