but with gottlieb they have 2 transformers, both with 110v primary windings. If you need to run them off 220v to 240v you wire them in series. If you need to run them off 110v then you wire them in parallel
COOL!! Thanks for this info, ive never really taken any notice of the primary wiring of the gtb transformers. That means i can remove the big, ugly stepdown transformer that is fitted to my Roller Disco (was in there when i got it) and just wire the transformer primaries in series 
just make sure you wire them as per the diagram.
when looking at the diagram you will noticed that the gotlieb transformers have 2 primary winding on each.
