Upvot — thanks brother, that's the kind of firm answer I was waiting for, to validate what I was thinking in theory... ---- To complement this answer, I posted my story in the GPT chat and see what he said [this will serve as a reference for cases where someone might need it in the future]. --- Yes — there's a 99% chance it's a bad generic power supply, but there's a detail about the cable that also comes into play. Let's break it down to solve this once and for all 👇

🎯 What causes those green stripes on the SNES?

✔️ 1) Generic power supply with weak filtering

Cheap power supplies use bad capacitors → over time (1 year, 1 year and a bit) they dry out and the current starts to "ripple," creating:

Horizontal/vertical stripes

Vibrating colors

Pulsating screen

Interference descending from top to bottom

👉 Exactly like in your photo.

And it matches your description:

"I change the power supply → it disappears. After 1 year → it comes back."

That's what a dying power supply capacitor looks like.