@carolinehuizar Some things I would try first is to check the pins on the cartridges that are problematic.

Try cleaning the pins on the console and the cartridges, But mostly I'd open up your games that are causing you problems, check for broken connections to pins or chips, best to use 91% Isopropyl Alcohol and tooth brush to clean the board. I hope this'll help you out.

Have you tried moving the contrast wheel?

Try opening the cartridge to see if any traces are damaged.

Depends on how high you dropped it and what angle did it receive impact.

I had a very weird problem with my Nintendo 64. When plugged into RF I would get a little static on screen, the RF cord was fine. But, when plugged into composite video would be fine, I found out that my power brick was slowly going bad and got a new one. I'm posting this here if anyone has a similar problem, If you have little hints of static dots, it might be time to replace the power brick, Thank you.