Cheetah MD16 display

[lagoogy]

Hi all, I wonder if anyone who knows about electronics can give a clue as to what could be wrong with my MD16R drum machine?

The display is not lit up and only displays a series of black blocks. It has had a new screen placed inside it, but the black blocks still display.
The drum machine plays sounds etc, and I cannot see any battery leakage(had a new battery put in).

Any help would be greatly appreciated.