LCD displays visual perfect, no response

Trying to fix my galaxy s4 and the screen is totally unresponsive to touch. I've replaced the digitizer and front frame assembly kit twice. The first time I figured maybe they sent me a faulty digitizer so I returned it no problem and ordered a new one from a different vendor. This time yielded the same result screen works no touch response. I'm fairly certain its something to do with the LCD connector strip that connects the digitizer but cannot figure out what's wrong with it. Am I going to have to purchase a new logic board now? What were possible causes that could have effected it when I replaced it?.

I'll also add that i initally attempted to replace just the screen and that's what initally broke the digitizer.

Any help is greatly appreciated