Those blinks [flashes] are fault indication (Error Codes). From the number of blinks occur at one time switch ON, you can get an idea about the faulty circuit section inside it. This will make repair easy. These are called blinking codes. Make sure about the exact number of blinking of the standby/power LED, by switching On & OFF the set, for at least two times. Count it carefully. If you wish to get some details, check the site linked here. It has details about blinking codes, and fault locating procedure, to many popular brand TVs and other devices.
If blinks continue without any pause, or the LED light stationery; the main board is faulty.
Search the site by type in the "brand name" to your device; [Exclude the model number], in the "Search box at the top right of the display window of the Homepage" to get gathered related posts. See the site by a desktop. Mobile view has no search box. If you are viewing it by your mobile, see it in webview/