Planned to build a printer with my 11YO son, but as work and other duties kept getting in the way, decided to just buy one for now, and continue the build in our free time. The one I bought is the 3DP-13 (link keeps redirecting to robot filter). He put it together all by himself, so the instructions, or what they provided in lieu of actual instructions did the job. He printed a lot of stuff in the first week, learning what he could do and not do. Then on Christmas Eve, the driver IC for the extruder stepper went up in smoke - an flame. It burned the board top and bottom, so it's dead now. I have emailed HICTOP for a replacement board, but I don't know how long it will take to get it, or, for that matter, how long the new board will last. So, I'm already thinking about alternatives. The mechanics of the machine make it worth the $300 price tag, IMHO, so even if I have to use something else for electronics, I'm not too upset about it. If memory serves me, it uses software called "Merlin". I don't remember for sure, since it won't turn on and I can't check it. But, it's fairly intuitive to use and doesn't require any modification of gcode to work. (My LinuxCNC plasma table requires that I tweak each program so that it will run. I don't want my son to have to figure all of that out.) I have read some about using an Arduino to run the machine, but my understanding is that I have to connect to the computer. The existing assembly/software just reads directly off the microSD card, so it is completely standalone. Are there other boards that could work? Below are the I/O for the board that was in use.

hot end supply output
thermister input
hot end fan supply output

X limit input
Y limit input
Z limit input

X stepper output
Y stepper output
Z stepper output

driver board cooling fan output
power supply input
controller/LCD I/O

The board appears to be wired for a heated bed, though it didn't come with it. Presumably, the other connectors would be for the heater and some sort of feedback?