This is a fork from https://github.com/Creality3DPrinting/CR10-Melzi-1.1.2
The files that Creality3D provided are neither the Source or Open and as a clone of the Melzi design which is under GPL Creality3D should have released the real files over a year earlier than the subset that they released now. Furthermore all Creality3D does is dumping the files on Github and not supporting them in any way. All issues with the data seem to be ignored as well as any request.
Their supplied "CR-10 Schematic.pdf" does neither match the "CR-10 Motherboard.PCB" file, nor is it the source-file but merely a picture. For example, the controller is named U5 in the schematic but U8 in the board-file. And the jumper J5 from the schematic to switch VCC between USB and the 5V regulator, it does not even exist in the board-file. Yes, there is an issue open for that: Creality3DPrinting/CR-10#1
So, why the fuss, why this repository? I still do care about the repairabilty of my CR-10 and Ender-3.
So I did my own version of the schematic from scratch based on the Ender-3.PCB in the Ender-3 repository. This is my try to provide data for the V1.1.2 board as I believe Creality3D should have provided themselves when starting to sell the CR-10 at least.
This is a complete Altium Designer project now, saved with AD17. Note: the "CR-10 Motherboard.PcbDoc" is not the same as "CR-10 Motherboard.PCB", it is based on that file but already has a couple of bugfixes implemented. Not to change anything, but to correct the faulty patched mess of the "CR-10 Motherboard.PCB".
I would have loved to work on this together with Creality3D but I can only guess that they are not interested in really embracing open source.
When I received my first Ender-3 it had a board installed in it with "V1.1.3" printed on the silkscreen. I asked in the Ender-3 repository what changed from "V1.1.2" but got no answer to that quesion.
I am still not sure but I believe the only difference is that the header EXT-A2 has been replaced with a 100µF/16V capacitor.
The Ender-3 at least has been quietely been "upgraded" to a "V1.1.4" revision of the controller-board. I only had pictures to work with but the only change that I found is that the FT232RL has been swapped out for a CH340G. I find that is a bold move given that the USB chip provides the 3.3V for the SD-card and while the FT232RL is rated for 50mA, the CH340G does not even have a rating for the output current in the datasheet. I would have added a small LDO for the 3.3V in addition but Creality3D did not.
I would not be surprised at all if this turns out to be a major cause for broken V1.1.4 boards.
Next thing I learned is that Creality3D started to offer a silent upgrade mainboard. What they did is to replace the A4988 stepper drivers with TMC2208. This is just a drop-in replacement and they did not change the board for it. Also if you did receive your Ender-3 with a V1.1.4 board you likely have A4988 drivers installed. Looking at a still from a Youtube video they changed the sense resistors from 0,1R to 0,15R. C10, C14, C18 and C22 should have been changed to 22nF.
Original content of the README.md:
CR10-Melzi-1.1.2
The CR10 Melzi 1.1.2 3D Printer Motherboard is now fully Open Source Hardware Association Certified.
UID:CN000004 https://certification.oshwa.org/list.html
Hardware and software licensed under the GPL v3 license, documentation licensed under CC BY-SA 4.0 International license.