Vintage Synth Repair

Hello group,

I acquired a Roland E-10 off a certain auction site, and having put
right the damage caused by some other person attempting to repair it -
many stripped via holes, missing tracks - I am left with a small
problem with the eprom. It seems to have a blank hole in the middle of
it; I dumped the contents, and was looking through it to see why the
cpu seems to hang somewhere in the power on routines, and there is a
256 byte hole in the middle of the code. 

How can I get a ROM image for this keyboard? All advice gratefully
welcomed!

Nik