What causes this horizontal line noise, how to fix?
 

Panasonic AG-1980

This starting happening all of a sudden and it is affecting all tapes and speeds.
The width varies but it is always in the same position.

I would be sure the heads are clean, but also make sure there is not some oxide build up elsewhere in the tape path especially around the head drum area. Keep us posted.

Thanks

Luckily nothing serious. I jiggled with the circled part, back tension lever I believe, and it fixed it. Loose tape I guess.

Make sure that tension lever moves freely, I would put a dab of oil at its shaft where in swings on the chassis, that would free up any crust buildup there and your tension will back to normal.

Those screen caps are seriously overblown values.

Either
- bad source tape, overexposed source (unlikely since TV)
- bad caps on the deck

I think they're fine. Face/Off was graded that way for the flashback.
Here's some more, including a comparison with an existing YouTube video - mine is much less saturated.

Yours isn't really less saturated. It's overexposed. The whites/highlights go hot, colors drain.
That points to a caps issue.

How does it look with both TBC on and off?

Oh, I see what you're saying. It looks the same on or off.

That's a caps issue. I have the same problem on a unit here. Too hot, needs refurb.

Do you happen to know which area of the board these caps are at?

Mostly TBC board, but can be others. And then you probably need to adjust the pots.