NES display problem, please help!

Hi. I just got a NES for my 10yo son, but I’m having problems with the display, see the pictures below. The seller says everything worked perfect before posting the package. Sound works, controller works, and the games a sort of playable.

So far I’ve tried

• Connected to several TVs via AV
• Tried four different games
• Cleaned the 72 PIN connector

Could this be a bricked RAM? Where should I start to fix this? Any ideas?

Thanks in advance for your help!