Hmmm, I’m not certain I understand that question. It appears that it can only be installed one way, with the lever open at the top, as indicated in this image.
No worries, I’ll walk you through how to test it out!
Because the switches are either NO (normally open) or NC (Normally closed) on a physical level the printer needs to be able to determine which the endstop is operating in. If the endstop is NC but the printer thinks that the endstop is NO, it will be inverted and will read as triggered until it is pressed. The opposite applies the same way.
So the easiest way you can test this would be to press down on the limit switch to invoke the opposite reading and see if the bed starts moving. If it does you know that the switch is inverted and I can teach you how to fix it.
If the bed still doesn’t work on its own are you able to move the y-axis at all using the on screen commands? You may have to turn off soft stops to get this to work but try and see if you can get it to move without that first. If you have no luck I can see if I can remember how this is done on this printer.
Hey Matt,
Thanks for getting back to me. I’ve tested with a known switch and motor and I am unable to move the Y-axis at all using the on screen commands. I also tested pressing the switch and nothing happened when I tried to move the y-Axis. Also, when I try to Auto Home, there is no movement on any axis, X, Y or Z.
BTW, I cannot locate the Soft Stops with the f/w that’s loaded. That’s the f/w that you pointed me to.
Hmm ok,
Yeah usually soft stops would be something you would need to turn off through a terminal interface such as pronterface.
I am thinking that either the y-motor or driver is dead. Preferably the motor would be the one to have died, as this is much easier and less expensive to replace than a mainboard. If I remember correctly the y-axis homes first when doing auto homing, so if this is not happening correctly the other axis would never get a chance to home themselves.
The 2 printers that you have here may end up turning into 1.5 functional printers in the end. We can probably combine working parts of each of them to at least get one up and running for the time being and then you can get replacement parts for the other printer. My first suggestion would be to try and take the y-axis motor that you know is working from the first printer and put it onto the second one that is not working. Then try it again!
Good news! I now have two working printers. I flashd both of the non-working printers with Marlin DW7.3.1 f/w and the unit that kept climbing up the Z-Axis now works as it should.
So I have one printer wth direct-drive and one with Bowden tube, both working.
That leaves the non-working unit with the Y-Axis issue. It currently does not have a Y-Axis motor, however, I did mount a working motor and the problem persisted. SO in summary. I have tested with a working switch and motor and still no movement on the Y-Axis. After all that, I’m guessing it’s got to be the board.
So I decided to upgrade the f/w on the direct drive printer. Prior to doing that the Info screen showed 5 for the Z-Axis after I auto-homed, now after the f/w upgrade it shows 12. The Z-offset was -3.4 before the upgrade, now it appears to be -2.6. Is that possible?
Hey! Congrats on getting this working!!!
Without changing anything on the hotend that shouldn’t happen at all. It could possibly be caused by an offset built into the firmware to allow for smaller numbers, but without looking into it I am not sure. As long as it is working ok I wouldn’t worry about it.
Now, for the one that still isn’t working. Mainboard seems like a good potential candidate for the issue. Can you test the continuity of the cable to see if there is something wrong with it? Or if you don’t have a multimeter you could pull one from the working printer and see if it goes.
Good morning Matt,
I’m pretty certain it’s the main board as I’ve tested with known-good cables, motor and limit switch. I can think of nothing else to try.
Cheers,
Len
Darn, that’s not the answer I was hoping for!
Are the other 2 still going ok?
No worries. The Direct Drive is still working. I haven’t played around with the other printer; just checked that Auto Home worked.
As for the third printer (Y-Axis not moving), I was abe to cannablise another CR-20 and got the main board. Hopefully it will work. I’m just putting it back together as I type.
I’ll keep you in the loop.
Great let me know how it goes!
Ah, no joy. Still no movement on the y_axis. The motor checks out good, I’m going to pin out the cable just to be certain. Otherwise, I have to assume that the replacement board was likely pooched since it came from a ‘donor’ printer.
Arghhhh!
I have a spare stock cr-20 pro board as well as two Bigtreetech skr mini e3 v2 boards that I could donate to your repair cause. I don’t imagine I’m ever going to need them so i’d be happy to see them get used.
Hey Blair, that’s very nice of you. How can I arrange pick up?
Cheers,
Len
I think I saw in a different thread that you’re in Ontario. I would need to ship them since I’m in BC.
Come to think of it I also have a stock Ender 3 v2 board and display that are unused as well.
Are all three of the printers you’re trying to get going cr-20’s?
Hey Blair, yes they are all CR-20 Pros. Can the CR-20s be modded to accept the Ender 3 board and display?
BTW, I would be more than happy to pay for the shipping. It’s the least I could do.
BC, you’re in God’s country! I love it out there. Spent some time in Powell River and Port Alberni.
Cheers,
Len
The footprint and mounting for the Ender boards is the same as the Cr-20 pro. The screen you would need to come up with an alternate mounting solution. It is in a case but the bracket for it is intended to attach to 4040 extrusion. The Ender 3 v2 board I have had stock firmware so that would need to be updated to a version for bltouch.
The skr mini boards have a different connection for the display than the stock cr-20 board. There is an older thread on here where another user showed the pinout to use the stock cr-20 screen with the skr mini board. It is apparently compatible but not plug and play.
I had compiled my own Marlin firmware for the skr boards but you could likely find a compatible version for your configuration. I think all you would be looking for would be firmware for an Ender 3 with bltouch. Firmware for Ender 3 v2 with bltouch may not work on the skr boards if you’re using the Cr-20 display because the dwin display on the Ender 3 v2 uses a different graphics library.
Good morning Blair!
Thank you for your detailed explanation. I suppose nothing ventured, nothing gained would apply here. I’m willing to do some experimenting.
My background is in IT. After about 40 years in IT I finally retired from my position as a network technician with a local school board.
I thought getting into 3D printing would help keep my mind active with all the learning, not to mention the frustration, LOL!
Let me know how we should proceed.
Cheers,
Len
Hey Len, I spent most of the day going down a rabbit hole trying to get the CR20 display to work with the Bigtreetech boards. I didn’t have much luck. At best I was able to get it to display the Marlin home screen but the encoder wasn’t working to navigate the menus. I know it should be possible but it’s a fun game of trying to figure out the pinout for the display, the board, and which firmware settings all work together. I’m throwing in the towel on that one since I need to move on to other projects and I wouldn’t want to take all of the learning opportunities away from you. 
The Ender 3 V2 display I’ll send should also work with the BTT boards since there is a section in Marlin specifically for enabling that screen.
I also have two Micro Swiss direct drive extruders that I’ll put in the box. They have the Micro Swiss heatsink attached to them but no heat break, heat block, or nozzle. You can also bolt a Cr20/Ender hot end to those extruders though. I saw that at least one of your printers has direct drive already so I figured this way you could get the other two upgraded to match. Those Micro Swiss direct drives were probably the best upgrade I did for print quality consistency so its worth swapping them out, and like my spare boards they were just sitting in my spare parts box and I’m not planning on using them again.
If you want to send me a message on here with your address I’ll box this stuff up and try to get it in the post next week.
Here’s some ‘light’ reading about the 12864 displays that might help your journey of trying to get it to play nicely with the boards:
https://www.reddit.com/r/BIGTREETECH/comments/i5w3mc/skr_mini_e3_with_mks_mini_12864style_displays_eg/
https://reprap.org/wiki/MKS_MINI_12864
I’m also going to toss in a micro sd card with the firmware (bin and source files) I was compiling today to test the screens. It is the most current bugfix version of Marlin and the configuration is based on what I had compiled and was running previously but it isn’t tested on an actual printer since I didn’t feel like cannibalizing my printers for testing today. Getting into compiling your own version of Marlin is a whole different can of worms to get into but you’ll quickly see that there are a lot of handy features that you can enable to add more functionality to your printers that didn’t come enabled on any of the older Creality firmware.
Again the firmware I was playing with today isn’t tested so it might need some small tweaks but it would at least give you a solid jump not having to start from scratch.
Hey Blair, sorry for the delayed reply. You are amazing!!! Thank you for going through all this trouble. I certainly do appreciate all your efforts.
Rather than post personal information on here, is there a way to PM you?
Cheers,
Len