Chosen Solution
the internal display only works when a external via HDMI is connected, at that time both internal and external work perfectly, disconnect external and nothing but garbled horizontal lines, replaced logic board and display with no positive result still same symptoms
It was the LCD after all , I originally tried what was supposed to be a known Good lcd and then was unsure after symptoms did not change.
Your logic board has a problem somewhere within the video logic. What you are seeing is the loading of HDMI port appears to act as a signal load as the internal one has failed. Someone with good board diagnostic & micro soldering should be able to fix your logic board. Otherwise you’ll need a new logic board.
