Graham, Gunnar and Chalky,
I have found that it is possibile to load or save the OS by pressing "One touch" + "Piano" + "Intro" while powering on the keyboard. The problem is that I have no copy of OS 2.0 because it was installed by a Roland authorized center. I have tried also to save the OS to a floppy disk, but it gives me an "error while reading" message, so I guess that there is really a problem with ROM. I would like to try to re-load again the OS itself, but don't know where to download it from the net. I have found a version of OS 2.0, but it's for VA76 only (seems that for VA7 you cannot do that yourself). So I guess that my main problem now is to found a copy of OS 2.0 for VA7.
Any ideas?
Thanks,
Andrea