New to this hobby and trying to repair all problems on my Fireball 2 pin. Teaching pin repair myself and have lots to learn. I enjoy the challenge as retired and need something to fill my time.my problem is 3rd flipper on top of play field flutters when you hold down left flipper switch. I understand how the coil works and checked small wire on coil and seems ok. Is this hold coil activated by contacts on lower flipper ? where should I look ? This form is awesome wealth of knowledge and would be lost without it.