There should be more of these around. Maybe hiding in the basement of a high school or storage room of a University.
[Updated: November 25, 2022 We found a second 775a in Dave Brown's collection of impressive synthesizers. Dave did some repairs on his AMF 775a and even drew up a schematic for the computer. By the way, take a look at the rather magnificent modular synthesizer he built!! And while you are there, take look at his visit to Raymond Scott's Electronium.]
[Updated: July 20, 2023. We have located another 775a and we are happy to add it to our collection. It arrived at our museum today. The computer is fully functioning and was restored by Matt Kamna out in Portland, Oregon. We will post more on this computer in the future.]