Capacitive sensor cable broken

[Helvetosaur 5]

Hi all,

After the auto leveling procedure on our second UM3 failed repeatedly, I found the article that said check the capacitive sensor cable - and after pushing the wires around, found that the red wire was indeed broken.  It looks like the cable is a separate part from the sensor itself, but it's not obvious how to connect them - is that a solder connection (as some other posts seem to indicate)?  Is it advisable to change out the sensor at the same time?

 

I am also a bit in doubt as to how to remove the sensor itself from the hinged fan/nozzle cover.  Is there a recommended procedure for that?  The little clips holding the sensor seem very tiny and delicate.  Should I be removing the entire fan/nozzle cover assembly (after unplugging the cables)?

 

Thanks in advance,

--H

 

[tomnagel 126]

The silver colored receptacle on the small white pcb is designed to insert the metal conductor from the red wire. When it is new, it can be pushed in without any tooling. But from your picture it is clear that the conductor is broken, and is probably still in the receptacle. This will need some improvisation from your side to repair it if you want to do it yourself.

You can also order replacement parts from your local reseller, and they will be able to provide you with instructions.

[Helvetosaur 5]

I ordered the replacement cable as well as the sensor board and they got here late last week.  I will hopefully have some time to try and fix it this week.  I am still in doubt as to how to properly remove and replace the old sensor board, the attachment to the head seems tiny and fragile, and I don't want to break anything.

[gr5 2,167]

This probably isn't the best video because you probably don't have to take it apart this much!  But this shows you how to take apart everything in the print head:

 

 

There's a good chance that what you need to do is much simpler.

[gr5 2,167]

By the way, instructions for changing that for the UM3/S3/S5 will all be the same.  So don't worry if you have a UM3 but the instructions are for an S5.  It won't matter.

[Helvetosaur 5]

So I managed to get the sensor board and the cable replaced and the machine is now fixed - now detects the bed correctly and auto-leveling runs fine. Thanks for the info and the links.

 

That being said, I find that the whole cabling arrangement of the head is one of the poorest engineering implementations I have seen, the cable routing is awful and the wire gauge/connectors are tiny.  Plus the sheet metal "pins" that hold the sensor board in place are actually too fat to fit in the holes in the board, requiring a lot of pressure to either remove the board or replace it.

 

[shocky2018 4]

I just changed the whole capacitive sensor assembly. wasn't to bad to change out in my opinion. I do not keep a spare on hand.

[gr5 2,167]

Usually it's not the sensor but instead is related to the middle fan.