Just thought I'd let everyone know that I have managed to solve the flashing '88' issue. I installed Un0, thinking that might work, but the flashing was still there and I couldn't get into global mode.
Having read somewhere that it was something to do with RAM tests on startup, I replaced my RAM chip with a suitable one from another manufacturer, and..........Bingo!
All working fine now. I hope this helps others who may have a 'bricked' FCB1010.