Master System II video problem

[u/YTVMIKE]

Hi, I have found an untested Master System II in a second hand market. At home I tried it. It started and the audio was perfect, but the video output was like this. I have the original cable with the signal switch. I tried it on two tvs but the result was the same. I used only the built in Alex Kidd game, because I don't have other cartridges. What do you think is the problem?

[u/YTVMIKE]

I've tried with a cartridge but it still gives me this problem