I have an "Ice Revue": http://www.ipdb.org/machine.cgi?id=1262 . Here: http://www.ipdb.org/showpic.pl?id=1262&picno=20243 I would like the "upper bumpers left and right" to be able to kick the ball upwards through the lanes (if possible: also the two "lower bumpers").
Many Williams Pins have the bumpers and the slingshot-kickers run by direct current, example Big Deal: http://mirror2.ipdb.org/files/245/Williams_1977_Big_Deal_Instruction_Manual.pdf -> page-7.
Schema around 23-C,D,E / 24-C, D, E.
Pinrepair says: http://www.pinrepair.com/em/index3.htm#perform -> More powerful Pop Bumpers -> "Un-wrap three layers of wire (3 times 40 turns of wire)" -> increased power.
Question: Have You done "changing to DC" - results ? Have You done the "un-wrapping" - Results ?