Hi everyone, Thanks for all your help but I never did manage to get the S-550 working so I put it on ebay for a starting price of £15,I only had the one bidder so he got it for that.It was a guy from Roland UK who reckoned if he couldn't get it going,no one could! Anyway too cut a long story short it was harder than he thought so Roland UK are now down to just the 4 S-550 main boards.........I will say no more! I personally think the Intel CPU may have gone south,I had the same flashing lights behaviour with a SCI Sixtrak and in the end I replaced its Z80 cpu,which was socketed and it worked perfectly,although I could be wrong,I have a smattering of electronics knowledge but mainly I do it by deduction....lol Anyway as I still have the S-550 library and mouse I decided to buy a S-330 off ebay for £65 inc postage,its an american model so it needs a step down transformer and also a good clean up but it seems to work perfectly so all in all it ended up good,OK I only have half the ram but its a slightly more modern machine and sounds the same so the filters on it will be put to good use| Jason