What have I done? I am certain I was plunging the ball right round the orbit if I held the left flipper in. Now it never happens. Was I dreaming? Am I missing a rule here somewhere?

hmmm...yes thanks fellas, looks like I can not disable the gates either..test time.

The coil is fried. When I select disable the gate "yes", it stays able. Therefore I cannot disable the gate.. Because the coil is not working. All good thanks.

No you didn't. You told me to test it. You didn't ask for any results.

And then I collectively thanked you and PH_Mark ("thanks fellas", plural), for pointing out to me that this was indeed a hardware problem, and not a rule that I was messing up.

Then I wrote that the coil is fried. Maybe that is not exactly what is wrong, but indeed, something about that magnet is not working properly. Then I said "All good" because I found myself on the right track, and "Thanks" again. So I have thanked you twice.

I then went about swapping over the connection between the right and left gates, and found further evidence that there is something wrong with the left coil, because the right gate works when powered by the left gate power. Not so hard to investigate really. I have now narrowed the problem sufficiently to be able to ask my distributor for the appropriate parts for repair.

So again, thanks for putting me on the right track. I wish I could have typed that better in the first place to save putting you off side.