OK, my silly fault - after resoldering everything 3 times and it working sometimes and not others, i eventually clamped the EOS switch together and it was fine.  So the problem was the new EOS switch was just a little out of adjustment (there was a small gap between the 1st contacts).... a lesson for next time!

That will do it every time!

I repaired a Big Guns today which had a weak Left Flipper sometimes... after replacing the EOS switch and adjusting it correctly, it was all good.

A good lesson though... The EOS switch is a very important part of the older flipper assemblies, and MUST be adjusted correctly.