So my robot has a dr4b that was working absolutely perfectly about 5 hours ago. Then it suddenly started stuttering when it going up(seems fine going down). I quadruple checked all the connections(with a multimeter), the code, motors, shafts are not bent, no weird frictions, shaft lengths are very short. This has happened before and it stopped after I wiped the cortex and re downloaded but this time it just doesn’t want to work. (I think it just has competition death). I am wondering if anybody has ANY ideas to try. My code is linked here:

My guess would be wear in the motors themselves. You need rubber bands. In this situation, I would recommend triangle banding very highly. Plenty of threads here already about that. Triangle banding, when done correctly, gives your lift the same tension the entire way up and down, giving your motors a constant aid.

Already have triangle rubber bands. I have no idea why but I re downloaded the controller code and it fixed it perfectly?!?!?!

That’s what I meant

Definitely REPLACE the motor controllers. I can tell you 90 percent of failures like this are a result of bad motor controllers.

As I was just about to press the “Post a Reply” button, I realized that you figured out the solution right when I was about to post the solution myself
I was legitimately about to post information about downloading the code again.
Keep note that after a firmware download, the software goes to its’ factory default code (The clawbot code).

Can I call you Mr. Chocolate? @Dokkaebi

Hi 162a,

Most common cause of motors not working in one direction is a broken motor controller. It is extremely common for them to stop working in one direction only, but leaving the other fine. Feel them to see if any of them are hot, warm, or smell toasty since it sounds like its been a bit since it may have burnt out. Another thing is that since the lift seems fine going down, it might be gravity compensating for a bad motor. This could mean bad code (I’m not looking through it right now), a bad cortex port, or shorted motor. Try swapping around cortex ports. You really need to identify which motor isn’t running correctly, which should be evident if you feel the motor running or not, or violently shaking around. Once you identify the motor, or even if you don’t, take the backing off the motor and look for frayed wires. You should also do this if it ends up being a motor controller problem, because it is likely that the frayed wires touched, thereby shorting the system, and frying the controller. If you don’t fix that, you will likely just go through even more motor controllers.

Good Luck. See you tomorrow.