Dreamcast randomly returning to home menu

[WalterSobchak]

Hello,
I'm new to this forum and I couldn't find a fix for my problem so I decided to ask you:
I've had problems with my Dreamcast this summer because it suddenly returned to the home screen during gameplay. This was always preceded by a noise like when the laser returns to its outer position in the drive. So I adjusted the laser potentiometer screw and it worked fine without any issues even for games like Shenmue where most of the time I couldn't even get throught the intro movie. I played everyday but after that I didn't use the console for about 12 weeks and it remained in a cold and damp room of my house. When I put Virtua Tennis in the drive the game loaded up but suddenly the screen turned black (without any sounds) for about 2 seconds. Then it returned to the browser. Like before this issue is worse for some games but in games like Virtua Tennis it's occuring quite a lot.
Now I don't know whether I'll have to adjust the potentiometer again and maybe kill the laser off or the problem lies elsewhere.
Thanks in advance!