Neo CD minor troubleshooting

Hello everyone just a minor trouble shooting question, I have a neo cd console which you can play for a varying ammount of time before it says to insert a cd, but say I lay an empty game jewel case on the door of the neo cd top loader, I can play with no problems, any ideas?

What do you mean by "insert CD"? Does the system reboot and says insert CD at the start screen/Music CD-player menu or does it give the black error screen and says "Please power off"?

Yeah, it reboots to the cd player and I'm guessing it's saying to insert disc, since I lay something light on the door and then the world is all fine with the system.