Well just an update, before I in vested in 2 new Vistas i thought id have 1 more go at them.
Id check everything except the ribbon that joins the top board to the bottom.
After a good clean i rebuilt it and hey presto it bloody works.Now I cant exactly say what i did but can only think 1 off the pins had crap on it or was bent.
I still have 1 more to look at but fingers crossed its the ssme problem 