Quoted from PinballFever:By yellow dots, you mean more powerful coils?
Yep.
PBR sells orange (+5%) and yellow (+10%) dot Gottlieb Flipper coils that give that extra zip. They also sell yellow dot Pop Bumper Coils which give you zing. I wish they made orange dots for the Pop bumper coils but that has not happened yet.
I just installed Orange dot Flipper coils and Yellow Dots for my pop bumpers on my Surfer. Talk about zip and zing!
On a side note I never high tap my machines.
Ken