Problems with Rambo and z axis not having enough power

Hi everybody, I finally got my machine working, but when I lift the z axis with the Dewalt dwp611 router installed, it skips steps, ad just doesn’t go up. But when I take off the router, it goes up perfectly fine with no issues.

Any suggestions on firmware, or board?

I really have no idea what to do.


Have you verified accurate current values at the stepper motor drivers? Perhaps the motor doesn’t have the torque needed because it’s not getting the required power.

I have not checked, because I don’t know how to check, could you tell me how to check?

This sums it up best in my opinion. Do you know what type of drivers you are using, A4988, DRV882, TMC2208, etc?

The problem is that my board is a Rambo, meaning almost everything is hard soldered to the main board, including the drivers. So any other way I can check and change the voltage if needed?

The rambo current limits are set digitally in the firmware.

Configuration_adv.h setting called DIGIPOT_MOTOR_CURRENT

You can increase the current limit of the z axis there. I am not promising that this is the reason for your lost steps, this was just one of my initial thoughts. Additionally, I would check grub screws to ensure there are no shafts slipping.

The problem is that it just can’t lift itself when the router is installed, but without it it’s fine. Meaning that it’s a weight issue. And from what I know all the grub screws are really tight.

I don’t have a Lowrider, but I’ve seen a number of posts on this forum where Z weakness is traced back to mechanical issues rather than electronics. Not sure of your setup, but do not use both Z sockets on the Rambo board. They are wired in parallel and therfore give a fraction of the power to the two motors that individual drivers will.

Even with the dual endstops?

I belive you use E2 for the second stepper driver on Z on the Lowrider using the Rambo board.

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