I'll preface this with the disclaimer that about everything I know about 3D printer boards and drivers can be summarized by: about a month ago was the first time I looked at a printer's motherboard, and I've read some things about TMC2208/2209 drivers, but I honestly don't really understand a whole lot except 2208/2209 is much better than whatever else was being used previously.
So anyhow, I've been going back and forth with Anycubic support for a few months now, trying to find solutions to the print issues I've had. I'll skip the whole story and skip to current status:.
My initial print issues were mostly due to the heated bed expanding or warping as it maintained temperature with bang-bang heating. Those issues went away when I switched to a Marlin firmware with PID, but that came along with other issues, due to the firmware not being exactly right for the Mega Pro.
In the meantime, however, Anycubic support sent me a replacement motherboard. I highly doubt this will solve anything (not if I go back to stock firmware and the normal bed heating), but I figured I would check it out to see what I can learn.
Interesting thing - all the information I have been able to find online talks about how it has "ultra-quiet operation" due to the TMC2208 drivers.
It's got 2208's for the X and Y only, it seems, though. I'm wondering what these other drivers are that are used for Z and the extruder.
and could I possibly use the 2208's from the new board for the extruder or something?
I played a bit with Linear Acceleration, which VASTLY improved my prints, but at a cost - I have to keep my acceleration hella low, or it layer-shifts like crazy..