Marty,

Yep, can see the difference in colour - but the stickers and wiring are all the same, so i'm happy its the right one and the problem was caused further along the circuit somewhere.  Have checked the wiring, fuses and EMI filter which all look perfect.  The transformer is the only thing with corrosion in the machine.

Have checked with Markc and Tony from the Pinball shed, neither have any wrecked sys 11B machines, but Tony gave me the number of a guy who is looking into it for me.  Otherwise it might be a waiting game until one comes up.

Rob