So I've been troubleshooting my weak lower-right flipper problem and have some more info. This is getting strange and I need some suggestions as to where to go next. Basically, my current issue is best described thusly:
My lower-right flipper is weak when I hit the flipper button hard. A soft button press, or half press, results in a nice strong shot that backhands up the ramp nicely.
If I hit the button hard it's so weak that it barely makes it past the ramp flap.
It has nothing to do with the upper flipper because I taped over the leaf switch for it to test if that was part of the problem and the behaviour is unchanged.
How in the world would the speed at which I hit the flipper button translate inversely to the power of the flipper?
I can only think of one thing. The contacts on the Stern flipper leaf switches are not large round contact patches like B/W ones, they're thin 45º angled pieces of copper. Opposing contacts are at 90º to each other, so they form an X when they touch. Perhaps what's happening is that as the button is pressed in, and the leaf switches of the lower flipper come together first, continuing to press in causes them to bend together and the contact pieces rub against each other. A slightly rough surface might lead to less electrical contact as they rub.
A hard/fast press of the button makes this weakened electrical contact effect the stroke of the ball because the movement is happening as the flip is happening. I've already adjusted the contacts so that the lower flipper contact has minimal travel, but it's impossible to eliminate it because you definitely need to leave some travel for the upper flipper to stage them effectively during gameplay.
Is there a way I can smooth out the metal on the contacts? What would be the best material to use to do that?