Hey there today i turned on the machine and the x axis was jamming so i checked the wiring.
I got a Primo with the SKR Pro 1.2 and this housing with DP 15/25 connectors:
https://www.thingiverse.com/thing:4678675
On one x axis stepper the connectors were molten together and now i want to ask which cables i should use to prevent this. Some other connections are getting pretty hot but are not molten.
Best Regards
I had two different wires do that as well.
I soldered directly in one case and used a jst-xh connector set on the other. The jst connector socket side required soldering and a crimper was required for the plug.
You can also use the heat gun solder splice connectors that Ryan sells in the V1 shop.
I’m not much a fan of the stepper extension cables, even though they work for most users.
Thank you for the tipps 
I saw that i have some spare JST-XH connectors. I’ll try them.
That is pretty crazy, did you have them folded and taped?
I’d be really interested if you can dissect that failed connector and show us what the crimping looks like on this one wire.
I bet it was either a bad crimp or a bad locking of that pin that is the reason.
I’ve seen that before on 3D printers.
Yes they were folded and taped and i also put tape around the connectors. Maybe there was a heat buildup inside the tape?!
i cant get the cable out but if i look closely i see that the white cable was slipping out to the bottom and you see the loose open cable in the picture. Maybe that slippage was the problem. The white cable was the original shipped whith the machine parts.
It’s a dead connector. Snap it in half.
Interesting.
That’s not a pretty crimp, but it appears the source of the intermittent connection was the pin at the top not making good contact with the socket (body).
It does not appear that the crimp on this wire is the source of the problem.
Note the strands of wire in and around the crimp are not so badly discolored at the entry to the crimp. Note that the further up this assembly you look, the higher the temps were and thus the more discoloration/oxidation of the part.
Thank you for being willing to dissect that connector.
Yeah most likely. I just switch to JST XH connectors and that should do it… hopefully 
Thanks for the help!
be interested in seeing the the other end of the connector because its been very hot aswell
Wow, I did not think the steppers took enough amperage to do that!!
24V, 1A drive current. If the contact resistance goes up from a few tens of milliohms to something “crappy connection” You’re now putting like 1A through a 1 Ohm stepper in series with that bad contact.
The power going into that poor contact - depending on the driver settings say 1A or more at 24V - is potentially up near 24+ watts. 24Watts is equivalent to a somewhat low powered 3D printer hotend. No problem burning up a connector and melting plastic with that amount of available power.
The actual drops will vary depending on the specifics of the bad contact and the series resistance of the stepper. At some point a really high contact resistance means little current flowing, but then again a really crappy contact might be intermittent or even arcing.
Touché, lol, also I am still at 12 v and forget about 24v sorry
it works a bit differently
1Amp over 1Ohm is 1Volt voltage drop. then power is I * U and that gives us 1Watt which is still quite a bit for a connectior
Yes, it does… I didn’t mention the actions of the driver or the impacts of that poor contact connection in trying to establish the current we set through the circuit.
I made a mathematically simple but technically flawed explanation that doesn’t match the real world scenario of a “wonky connector” well enough. Odds are that the contact resistance was something other than 1 ohm, and that most of the 24v drop could be at that contact.
I should fix my explanation, but to do so I’d really need to guess about the poor contact, which might have even been so poor that it was intermittent and arcing. That changes it yet again.
The takeaway- that there’s plenty of power available to melt that connector- is correct, though.
Edit: Thank you for calling me out; it was a bad explanation and needed to be corrected.
