Hi RetroPin,
I got a bit keen tonite and wanted to see if replacing all the 4049's had worked. So, I scotchlocked the exposed G.I wires for bumpers & taped, double checked that nothing else was or could be exposed underneith then plugged display in & fired her up. To my surprise, all three are now working. I didn't run through the diagnostics as I didn't have enough hands but definately getting what appears to be correct on all! 
Soo the good news is that it may look like the SRC's on CPU are healthy. I was still getting some 'flaming' on the top alpha display (not sure what the correct term is) but I would bet that it is caused by the unbalanced +100/-100.
So hopefully I can pickup my PinScore LED tomorrow & put that in. The better news is that this one survived and I've got a spare, or pick up a bargain somewhere (MarkC???!!) to put it in. Taxi maybe or F14???!! I've still got some plastics for one of those too!
Good stuff Marty...
More Pinball techs than collectors on this site 
Yep, its a great mix here!
I ran the diagnostics (display test) and looks like I'm missing the 'f' segment. I believe this is controlled by U16? Which may explain the strange readings from that with the DMM? I will try to find one (maybe even s/h) just to complete the display and get it working 100%.
