Failing Rambo mini

LowRider CNC Troubleshooting
1

Hi everyone. I just finished my lowrider recently but now I believe my control bird is going bad.

I have successfully cut/drawn about 15 things but it’s periodically getting worst and the driver is failing on the x axis.
It started first with the x axis failing mid program and just shaking in spot. So it was as if I was attempting to move to the next step but wouldn’t.

It progressed to become worst and stopped shaking and just stoped moving at all. It also started to happen much earlier in the program.

My reasoning why I believe it’s the drivers:

  1. While malfunctioning if I switch the x axis steppers to a different drive axis they function fine. And if I switch a different stepper to the output of the x axis they fail. So that has pointed me to the board and not wiring.

  2. it will work fine again after a power cycle.

  3. I checked all conductance in the wiring and they are perfect.

So long story short trying to get some feedback if anything else I should try before I can get this replaced from v1

2

Sounds like it is overheating (if it just stopped). I would also worry about an intermittent wiring issue.

3

It doesn’t exactly just stop. Just the x axis either stops completely or shakes but doesn’t move.

At first I expected wiring too, but after I switch a different stepper to the x axis output driver and that fails it co firmed to me that it is the board.

I got thru one cut this weekend and then it failed about 50% in on three others.

4

So you swapped the wires and the stepper or just the stepper? I suggest just swapping teh wires and eliminate one of the more common issues.

The machine moves, it can be very hard to find this. Bad crimps, loose connection, and hidden tugging are all much more common than a bad ultimachine board.

Agreed, can you show is how you have your board mounted and wired please.

5

Just wondering if you found a solution to this. I’ve recently run into a very similar issue with my MiniRambo and the X axis. In the middle of the run the X axis will just shudder in place. Swapping connectors on the MiniRambo indicates that it’s a board problem, and it does go away with a reboot. Not sure why it’s failing, but I do suspect some back-EMF from moving the gantry by hand since the X axis is more likley to be moved.

My default will be to reassign the E0 pins to the X axis to use those drivers since I don’t want to buy a new board. I’ve got it compiled and ready to go but am curious about whether you found a solution with your problem?

6

I had the exact same problem. First x axis would shudder and now it doesn’t respond at all. I’va also traced it to the board by swapping connectors. Help!! Is there any solution for this problem?

7

You can change the pins file in the firmware to the E socket. But it is extremely hard to kill a driver on that board. I would tripple check the connections first.

1 Like
8

Yah take Ryan’s advice and check connections. My issue was the pin connectors for the stepper motor wiring harness. Had to solder together.

9

have anyone solved this issue?
i have gotten the exact issue with my mini rambo on the x axis
all wires are good . all connections are good. stepper motors are good aswell
when the problem happens the driver board by the x axis plug is extremely hot.
how can i change the pin files in the firmware ???

10

If it is moving I don’t think it is bad. Extreme heat could be from axis binding. The other thing that could cause it is accidentally changing the stepper current from the screen. Maybe double check the current, turn it down a bit. Take that belt off and make sure that axis moves free and easy.