I have recently purchased this system from the ebay seller.and there is no instructions manual in it. why my sega gen mobile wont turn on when there is no cartridge in it? does it work without cartridge in it? Or i have to buy a cartridge to make it work???? it says 20 built in games ready to play out of the box. And mine wont turn on.

Video Game Consoles & Games - Sega - Genesis 2 Console