I get scanlines when playing with Link, should I get a new cable?

I am currently using a relatively old cable for my Linking. I usually don't have any issues, until maybe 8 months ago, scanlines start appearing after 10-30 minutes in the headset.
I am finally fed up with the scanlines and wish to remove them. I have no idea why they show up, though. I'm thinking it's maybe the cable, because my hardware is good and the scanlines don't show up when using Air Link. No, I cannot use Air Link anymore.
The reason I need help with this is just so that I do not waste money on a cable just for it to not work. Should I get a new cable or nah?