Quoted from twenty84:
I think the main issue is that the TK lock is just a poorly designed mech. Both of us have spent a lot of hours getting our games set up and gone down some dead end roads that initially felt like they might be helping. I initially liked the fan idea and it may have merit, just can't convince myself that the temperature of the flipper coil is really the issue here. If it is an issue it is larger than just this game, and we owe it ourselves to know just how much difference it makes.
Temp is really the only thing that makes sense (as far as flipper performance), when you get the shot set up properly. You could always hook up a clamp meter (then push max read button) on the primary winding. Test on a fresh game and then test after 2-3 hours of play. Or maybe check it with a gauss meter to see if that value has dropped overtime.
Obviously there are other problems with the mech, but as you know you can mitigate those with adjustments.
Fans might drop the temp 5-10 degrees? Think I might go the LOTR coil route though, or just keep it disabled for now.