Ensoniq TS 10 doesn't load ROM sounds

Hi there,

I bought my TS last year in a perfect working order (serviced). However, for some time it has been producing keyboard calibration errors. Yesterday, however it froze while sending the sysex data from the computer. After restarting the display remains black apart from showing U0-2 in the left corner. Three indication lights are on: Sounds, Rom Bank Set 2 and Compare. I have attempted a hard reset but without any effect.

Would you be able please to suggest what issue this could be?!

Many thanks,