HELP on ThE Dc CONSOLE

Please, somethin is totally wrong wit my dreamcast. It won't even turn on anymore. I mean, I turn it on, and then 2 sec later, it shuts off automatically. The only way I can keep it on, is if I leave the lid open, but once I close it, it shuts off. It's not the games that's wrong, it the lid. I have opened my dc to see what is wrong, but everything looks okai (dunno for sure tho). Can someone tell me what's wrong and can you help me please.