When my KM3 took a dive, when the RS232 cable got pinched, finding the replacement boards was like panning for gold. HURCO said they thought they might have one, would need to physically verify, but wanted a King's ransome, more then I had acquired the complete working machine for.
Armed with all the drawings and still working amps, I decided to just replace the controller. Since the drives are analog velocity control, I went with EMC2.
It is still a work in process. But in the end I will have a maintainable machine without any hostage/ ransome situation. Even if the amps go, there are a lot of replacement alternatives when the controller isn't proprietary.
It greatly depends on your needs and use of the mill. If it needs to be up and running tommorrow to meet production schedule, the ransome may not be bad compared to a whole NEW machine and any lost revenue. If you have other machines, this is a hobby or limited use, then your horizon broadens. It also depends how much of the conversion you would like or care to do yourself.
I've seen many HURCOs on the web and this site already traveled down this path.
Isn't the KM3 iron Taiwanese, I recall seeing some Clausing (?) or others that obviously shared the same genetic background, or should I say mold/castings.