I go to use the machine this morning, and am in the middle of changing out the computer that controls the xcarve, and had the (sort of typical) inch vs mm slide scare. So I swapped back just to get a part done. Then I realized I was getting odd responses from the z axis. Up would mean up or down randomly. Reset the shield, used easel to set it up… Same. Rewired the motor at the shield, same thing. Went to rewire the block, and noticed this on the z axis motor…
Any ideas how this happened?
That was my thought as well… 
They were on the high side… Not jacked all the way but as high as they could while providing smooth operations…
Actually sort of hope that was it… But that clip comes from the kit… Not something you make yourself… A bit scary.
The motor was working… Evidently ground plays a role in direction… I would bet it works… Wonder if I could pull out an unused end and recrimp it…
Nah, the pin that burned was loose. Was able to easily pull it out of the motor… She’s toast. I’ll call inventables to see if they will replace it. In the meantime I same day ordered one that might work from Amazon…
The coil windings are essentially inductors. If the connector was loose and then slightly disconnected while there was current flowing, the voltage would spike significantly, enough to arc and char your connector. You’ll have to check with a new motor, but such a spike could have damaged your controller as well.
You can see an extreme example of this here. When the switches open, the current wants to stay the same, so the voltage exceeds the dielectric breakdown of air.
The motors I got with my XC are the wired type, rather than a connector, it’s much easier to ensure a solid connection that way.
the pin was loose. the plug may have been solid, but if the pin slips back the current will eat the pin. I see it every day.
Well if it had to be a motor, the z is super easy to change out… Amazon same day delivery for this guy: Nema 23 CNC Stepper Motor 2.8A 178.5oz.in/1.26Nm CNC Stepping Motor DIY CNC Mill https://www.amazon.com/dp/B00PNEPF5I/ref=cm_sw_r_cp_api_stazxbSRMFCSS
5 minutes to swap…
Eliminate the connectors. The quality of the plating and connection fit will all introduce a non visible variable that could scrap your job at any time. The only time you NEED quick change connectors is if you need to quick change something. Then you NEED to use the expensive gold plated ones. Not these.
