I've been having trouble with this for a while now.
On some early WPC games (like T2), I am able to install LEDs in the start buttons with no trouble, and the buttons function normally.
In some later games (shadow, IJ, RFM), if I try to install an LED bulb, it jams the button.
And yet, with AFM, I can install LEDs in the start and launch buttons.
Am I missing something? What's the trick? Why can I install LEDs inside some buttons, but not others?