It runs on original TOS with the internal RAM configuration, without the separate 4 MB expansion, which was removed for testing purposes and now sits set aside.
Everything in this machine was moved over to the Mega ST 4 "High" that I was given, including its original power supply. It's not really a parts donor though, it's simply the spare machine now that the new Mega 4 carries the main setup. Back then it had an intermittent fault: after being on for a long time it would eventually show a white screen on boot. I suspect it was again a poorly soldered CPU socket, though I never fully confirmed the cause. With the current setup it runs stably, and the socket in question isn't in use anymore.
+Everything in this machine was moved over to the Mega ST 4 "High" that I was given, including its original power supply. It's not really a parts donor though, it's simply the spare machine now that the new Mega 4 carries the main setup. Back then it had an intermittent fault: after being on for a long time it would eventually show a white screen on boot. I first suspected the 4 MB expansion and removed it, but the fault persisted. Only after reverting it to the old TOS and a fully original state did it run stably again.
A few possible directions for the Mega ST 2, none of them decided yet: