My Apollo II stops hashing after about 5 minutes from a reboot. I did notice that even when it hashes the fans show “n.a. rpm” despite the board being in the 80s on eco mode. I reflashed the device but still experiencing the same issue. My initial guess is it’s overheating since I’ve never heard the fans. When I used the device last winter the fans would spin up briefly on boot but that has not been happening.
Whoa . . . when you say "board being in the 80s on eco mode" I assume you're referring to the temp being in the 80's as in Celsius (not Fahrenheit). If so, that's too high and you are probably over-heating. And that's why it's stopping. Sounds to me like it's repair time if it's not already cooked. You might want to reach out to Futurebit for a fan replacement.
Cheers!