Hi All - We made great progress on our low rider, but we seem to have run into a problem.
It appears we shorted out the z control microchip on the Rambo board. It has a small blister on it which I’m assuming was caused by a short.
Since we have the parts from a never built lower rider 2, we are going to use that board (and SKR) to keep things going.
The question for the masses: we assume the board component failed b/c of a short. Is the best way to ensure we prevent that is to tape all connections to avoid the possibility of wires crossing or touching something metal?
Based on forum posts, it is extremely rare to lose only a driver on a Rambo board. I think this is only the third time I’ve read on the forum about a lost driver on a Rambo board in the last three years. Looking more widely at drivers in general, I read more about drivers being blown when they are energizing a motor and then the motor is disconnected than shorting. If it was a short that caused your issue, I’m surprised the fuse did not blow.
We just don’t want to short out another board.
Assuming the possibility of a disconnect rather than a short, consider doing a continuity test on the wires while manipulating the wires with particular attention to the connections.
If all you’ve blown is one driver, you can still use the board in a serial/series configuration. This is a bit more problematic for a Lowrider with the dual Z axes, but, historically, it was common for the MPCNC machines.
You could be right that this went when the motor was energizing and then was inadvertently disconnected. We have struggled with keeping the leads for the z axis that plug into the board to stay engaged.
Are there better methods than the plastic tabs that come with eh wire leads?
Also, our understanding is that you can’t series/serial the z axis.
We have struggled with keeping the leads for the z axis that plug into the board to stay engaged.
Are there better methods than the plastic tabs that come with eh wire leads?
With my electronic projects I do two things:
I include strain relief. I make sure that any external pulling on the wires does not translate to the plug. For my Primo, I brought my wires through a hole in the side of the case, and used zip ties both on the inside and outside of the hole. Pushing and pulling on the wires will not travel to the plug.
I glue the plug connection with low-temp hot glue. I didn’t do this with my Rambo board, but I often do this with other electronic projects.
Also, our understanding is that you can’t series/serial the z axis.
I’m not a Lowrider owner, but I don’t believe this is strictly true. With series/serial wiring, you give up electronic homing. If you had a setup where you could square your Z axis mechanically, then I cannot see a problem with series/serial wiring. For example, if you had a parking spot for your machine with a set of well calibrated blocks to rest the Z axis on, then your machine would be nearly as square as if you had electronic homing.
I second this. After you have confirmed the wiring is correct.
We used to use this technique when wiring board in offroad robots. If it is good enough for that vibration, it is good enough for sitting in the garage. It also does clean up easily, preferring to stick to itself. Just make sure you cut it enough (when removing it) to not make a loop around your plastic connectors. We used to just glue one side of the connector to make them easier to remove. The point of the glue isn’t to fight someone who tripped over the cable. It is just to keep the micrometer vibrations from adding up to make the cable loose.
The drivers do generate heat. They self protect, so I don’t think this is why yours popped. But any protection of them should include letting them lose that heat. On the rambo, overheated drivers shut down. On the skr, the tmc drivers reduce the current, which can cause lost steps.
An enclosure with some vents is usually sufficient. If you want to be extra safe, and enclosure with a vent fan, and if you’re milling metal, a filter is extra safe.
