BK is under repair. The way things look it'll still be at Eurocade 11.
A controllerboard pcb was malfunctioning. Forgot which one though ..... A guy I know -professional bicylcle pin-repair-guy took BK and he'll be modifing another Williams pcb to fit BK. He told me that it would be a slightly different pcb but that gameplay/sounds/lights won't be affected. Or else it's the easy (but expensive) route, get an original one.
Fingers crossed he makes it in time.