Just a thought before replacing the LCD clean the cable ends with IP alcohol . small bits of dirt or lint in the contacts can create a similar problem. If after cleaning you have no Joy then inspect the solder joints at the connection on the motherboard . Use a magnifying glass or loop for close inspection . look for cracks in the solder or missing pins is you see any cold solder joints cracks or dull solder . Use flux and a Hot air station to reflow the solder . If all seems well on the board end then try installing an new LCD. Hope this helps