I had the same problem. I removed the screen in order to swap the battery in an iPhone 5s. When I put the screen back I had black lines running down the picture. I tried removing and re-inserting the cables but it did not help. I then used a small amount of Electrical Contact Cleaner made by Silver Hook on the connectors on the board and on the screen connectors and then blasted them with compressed air. Reconnected all the cables and all was well again. Note: Make sure the phone is off when appying the cleaning fluid and when plugging in or out the cables. Hope this helps
What size is the tri-wing screwdriver needed to adjust the trackpad on this model?