One Faulty xbox


Hi guys, not been on here for a while, any xbox gurus about?
My grandsons xbox one x switches on for about 5 seconds then cuts out, nothing comes on the screen. Any ideas where to start looking please?
It could be something on the mother board, that is causing it to switch off , i would take it to the repair shop...or try to google the problem. i also have an xbox but older version