No display on Galaxy S7 screen, but sounds and buttons work.

[AC Question]

Hi I'm working on fixing a Galaxy S7 that was dropped and the screen shattered. I ordered a new screen and digitizer and was following several video guides. I was able to take it apart and was testing the screen before reassembling it and it's doing the same thing it was doing before. The light at the top flashes and the sound works, and I can hear texts/emails being received and interacting with the screen seems to have an affect, but the screen is still completely dead. Now I know it's not the brand new screen's fault, and worried that it could be the motherboard. Anyone else ever have this problem? How can I diagnose what's damaged? Can provide pictures upon request. Thanks!

 

[Rukbat]

That's why if you're not a tech in a well-equipped shop, you shouldn't be fixing phones. You troubleshoot the motherboard by replacing it with a known-working one. Oh, you don't just happen to have a known-working motherboard for that phone sitting in your motherboard box? Samsung does. A well-equipped shop that repairs Samsung phones does. (I don't any more, I'm retired, but I used to.) But that's how it's done. If a phone comes in that doesn't pay to repair, you save any working parts - for times like these.