Tronxy X5S with lerdge K board and bltouch: homing does not stop on Z axis

Can anyone please help me? When I home all on my Tronxy x5s, the heat bed continues to go up and doesn’t stop, like it doesn’t know when to, so it forces the printing nozzle thing upwards and the bed becomes unlevelled. When i use the setting to digitally move the bed up it stops about 2 inches below the nozzle. What is happening in both of these issues and how do I solve it?

Welcome to MakerForums!

It sounds like the first problem is the source of the second problem. Here are a few questions to help identify the source of the problem.

  1. Did the printer previously work, and it recently quit working, or has it never worked correctly?

  2. Have you made any modifications to the printer beyond the kit?

  3. Do you have any sort of bed level sensor, like a bltouch, mounted?

  4. If you start to home, and you press the Z limit switch, does it stop homing immediately?

  1. The printer has previously worked
  2. Changed to lerdge K mother board
  3. Yes, bltouch sensor
  4. I will test tomorrow

OK, so the problem is almost certainly in the connection to the lerdge K board, or in the software on that board. I don’t have any experience with lerdge K.

Since it used to work before you changed board, the limit switch probably is physically working and it’s more likely to be the connection to the board, so pressing the limit switch directly, it’s unlikely to help.

I have no experience with that board, so I don’t know how it is wired up.

Thank you for all your help so far, I have discovered that my printer does not have a z-limit switch. I have ordered one but is there another way to stop the heat bed from rising or is the limit switch the only way?

The Tronxy X5S I got had a Z limit switch. On each side, there is a piece through which the vertical guide rails and Z screw go, and to which are attached rails that hold up the bed. In the pieces through which the rails and screws go, there is a long screw. That screw presses a microswitch mounted above it. I know Tronxy changes its designs without noting the difference. I suppose they started shipping with a board that uses feedback, or started shipping with the bltouch and configured their firmware to use it for a Z limit switch, or something like that?

It looks like the lerdge k boards use proprietary firmware. Because of that, you’ll probably want to ask lerdge support for help here; if they keep their firmware proprietary, they should be providing support. But please do feel free to tell us about their response!

More recent Tronxy X5SA information in this reprap forum thread:,871114,871208

I see that there is reference there to completely removing the Z limit switch and using only the inductive sensor.