Hi Chris, I saw one of your recent videos with the AR4 drawing a skull. Could you please post a video of the AR4 MK2 drawing concentric circles and then it drawing concentric squares? Say something like 10" diameter circles, spaced 1" apart, down to a 1" diameter circle at the center. Similar for squares. This would be very useful for users to get a feel for the robot's accuracy. Thanks, Mark

We are debugging our AR4 robot. One thing we had wrong initially was the RJ-45 keystone jacks were swapped for 1 and 3. We mistakenly swapped the cables designated Top and Bottom in the manual. We have since corrected that and while the robot works we are now finding other issues. Can swapping cables 1 and 3 have a destructive effect on the Teensy itself? Is there a way to test the integrity of the Teensy as we've checked most other components. We want to rule out the Teensy as a problem. Thanks, Mark

I did my first boot up of the robot yesterday. Nearly everything was fine. The limit switches checked out. The encoders were reading. And all the motors could be jogged with the exception of J4. That one makes a small noise but doesn't move. I've verified that the belt isn't too tight. There is no difficulty turning that axis when it is not powered. So there doesn't seem to be anything mechanical holding it from rotating. We checked the motor cables (swapped a working one and it didn't make a difference). And we've used a multimeter to verify the wiring between the controller and the motor. However, early on we noticed some poor soldering of that motor cable. We mistakenly may have shorted across two of the four motor wires. We are wondering if that could have damaged the motor. Is it possible to damage anything in the motor with a faulty soldered connection? Can you suggest a way we can test this? If necessary I can order a replacement motor and encoder. Can I do this directly from StepperOnline. If so can you suggest a part number. When I search for it I get the page for the entire kit. Thanks! Mark