Thanks for the link, but as I said, the problem it's just that the composites disturb the signal, the VCR works fine. Besides, I can't afford to buy a new one, so I'm ok with just fixing that problem. I just wish I knew how :\
edit: I read your edit, but it doesn't suggest how to fix my problem.
Anyway, somehow VHSs are cooler than 4k TVs :D