I once bought a Spirit of 76 that had an after-market Wico sound card added. Someone had also installed a Bally chime unit that chimed at the same time. The chimes, intended for 50V, made very soft sounds in a 24V Gottlieb. I assume that chime unit was used so as to avoid drowning out the electronic sounds. I figured the electronic sounds were added so the EM wouldn’t seem so “old” after SS pins came out, similar to the way metal rail covers were put on some woodrails after the newer pins had metal rails. I thought the sounds were ridiculous, so I disconnected the sound card and swapped in a Gottlieb chime unit.

I’m guessing your Surf Champ also had the sound card added after SS pins had come out. Maybe the sticker on the machine also came from the sound card manufacturer, to tout the after-market “upgrade.”

It’s somewhat hard for me to understand how people back then (and I probably did as a teenager) thought the sound card (which I refer to as a “squawk box”) sounded better than beautiful clear Gottlieb chimes.