How can I repair the pen/touch interface?

Everything is working fine on my original Surface Studio except for the touch/pen interface. It started failing at the bottom of the screen and worked its way up. Now touch doesn't work anywhere on the screen.

I'd like to check for loose connections first, or signs of failed components. Any idea where the relevant modules are located inside? I already completed a fan replacement with the iFixIt guide but didn't notice any loose connectors or obviously damaged components at that time.