> Do you know that the display itself has gone, or could it be one of the
> driver chips or inverter that has gone (ie: the Roland MKS-70 right hand
> third of display is driven by a specific chip for some reason). Might be
> useful to check where that section of the display is powered from - might be
> a simple component swap out.

According to the schematics there's only one power line for the
display as a whole. Also, it's specific segments in every character
that have gone, not a whole section of the display.