Motor Wire Connector Fried


#1

Hello Everyone!

My Z-axis motor hasn’t been working (not moving the platform up and down while it tries to print). I opened up the printer and the wire connector next to the motor driver chips are burnt (picture attached). Everything else looks fine to my eyes at least.

Could I just find replacement connectors or is it more complicated than that? The connectors are labeled “msh 5, 2695” but I haven’t been able to find the same connectors online anywhere.

I contacted support and they just recommending a RMA for $1300. I’m hoping with some work I could avoid paying that much. Any help is greatly appreciated. Thank you!


#2

It’s definitely worth unplugging that connector and inspecting it and the area more closely. Look for signs of shorting.

However it’s also possible a failure in the electronics or a short in the motor itself caused overcurrent. If that’s the case your problem might be elsewhere in the circuit.

If you measure the pitch (center distance between pins) and other dimensions you should be able to use the filters at Digikey or Mouser to zero in on the exact connector. Someone else here might be able to point you to an exact model.


#3

Thanks for the feedback! I’ll definitely try ordering a replacement and see if that solves the issue.


#4

The problem happens when connectors that carry a decent amount of current oxidize with age. The resistance of the connection increases. And since Power (Watts) = Current^2 * Resistance, as the resistance increases, the connector gets hotter and hotter. It can be fixed, but you have to be careful. The female connector should be replaced. The male pins are soldered in to the PCB and they’re going to be hard to remove/replace without the right tools. So you’ll have to clean up the pins (which ought to look “carbonized” when you inspect). But the stuff you scrape off in order to expose bare metal is going to be conductive, you have to keep it from escaping in to other areas of the circuit board.

Personally, I’d eliminate the connector entirely and just solder the wires directly to the posts. The connector is there so it’s easier to assemble and disassemble for Formlabs. It doesn’t need a connector unless you want service from FL (they won’t service a modified machine). And soldered-on, you will have eliminated the failure mode completely. Replace the connector, over time it is likely to fail again the same way… especially since, if the posts were originally gold plated, you’ll have removed that plating leaving the posts more prone to subsequent corrosion and increased contact resistance.