There's any easy way to tell if it's the button optos. Grab the flipper, then press and hold the flipper button. If it's working correctly, you'll feel a single tug on the flipper, then light steady pulling due to the hold coil. If the opto is bad, you'll feel a constant tug or buzzing and hear a hum. The GI will dim, too. The optos can often be cleaned, but if one's bad, you can buy the whole board for about $20 and change it without soldering.

The EOS actually does very little in a fliptronic game, because the system is designed to work without it if necessary. Experienced players might notice a subtle change in aim timing, but the play is otherwise normal.

Excessive slop in the flipper link is the other major cause of weak flippers, especially in the newer Stern games which don't have the EOS, or which have it but don't use it in the flipper coil timing.

There are 5 different strength coils; make sure both of yours are correct.

Loss of power is never caused by dragging of the mechanism parts. If anything is dragging, the flipper will tend to stay in the raised position, which will be detected long before any real power loss occurs.

Allan

I agree completely.

I'm aware of the white ones allowing light through. I got some brand new ones like that. The solution was to color them black with a paint pen or sharpie. Was there another failure you had in mind?

Allan