Been considering doing a repro board for this one. It'd be fitting since the first solid state pinball machine I ever had was a Hot Hand and in 2011 I spent a few weeks documenting what I could understand about the SB-100 sound board @ http://www.techdose.com/projects/Stern-Pinball-SB100-Sound-Board/346/page1.html

I'll see what I can whip up in PCB software over the next few days. Try and order in a prototype with the next round of boards I'm putting in soon. Will probably just drop all the chimes circuitry as the later REV SB-100 boards did and just go with the tones only design to simplify things.

Incidentally, I've got maybe 6-10x used boards as well that I'll be putting up for sale. At current, a good number of them are "mostly working" and shouldn't take too much to get fully working. So if anyone's interested.. PM me. It would be a good push to get those gone through & work on a prototype order for the SB-100 at the same time. The used boards would be gone through -- new electrolytic caps, new headers, verified working. Probably be in the $140-160 range fixed up. Would need to know if you need a board with the chimes circuitry or without. I've found the ones with chimes circuitry to be noisier FWIW.