UM2 - Replacing heat cartridge and PT100 B Sensor

[closedcircuit 1]

I need to replace both the heat cartridge and PT100 B Sensor on my UM2 (basically, the cables "drowned" in melted PLA which was then impossible to remove without damaging the respective cables).

Could someone please point me in the right direction in terms of how best to replace these two items (e.g. is there a good guide or video available)?

Cheers

Phil

 

[IRobertI 516]

This is a good video that shows how to disassemble the head:

 

Getting the sensor out might require some patience as it has a tendency to get stuck in the hotend. But since you're replacing the sensor you can be a bit destructive about it. Perhaps screwing a small screw into it to give you something to grab onto (that might expand it and lodge it even hard though)? Very very carefully drilling a small hole from the front so that you can use a paper clip or something to push it out?

 

[closedcircuit 1]

Thanks a lot Robert. It is indeed a good video, but I was wondering about the other end of the cables (where/how to plug them).

I should have been clearer in my original message - sorry.

 

[IRobertI 516]

Oh. Well you can just look at where the original ones are plugged in. The temperature probe is connected to TEMP1 on the board. It has a little locking tab that you may need to lift slightly to get it off.

The heater is connected to a green screw terminal in the corner of the board. Unfortunately you can't reach those screws without also removing the board. What's even more annoying is that you have to also remove the left white cover (that hides the stepper motor) in order to reach one of the four screws that holds the board in place. It's not difficult to do, just annoying. I would start by removing the cover, then lift the bed, then lay the printer on the side and finally start removing screws.

Also, before you pull the old wires through the black wire mesh, attach the new ones to the old cables so that you can use the old cables to pull the new ones through. Cover the sharp bits of the connectors in blue tape so that they slide through more easily as they have a tendency to get caught in the wire mesh.

 

[closedcircuit 1]

This is really useful and practical guidance and exactly what I was looking for. Many, many thanks!

 

[damfal003 0]

Hi closedcircuit, do you know what caused the "drowning" of the filament? Because my friend has had the exact same problem and I'm replacing the PT100B on his after he stripped it from the socket trying to cut away a huge block of PLA. However, he doesn't know what caused it and the best I could give was to make sure the Bowden is all the way into the PTFE.

Cheers

[swordriff 119]

If the Teflon does not press down hard on the hot end inside the steel coupler, there can be a leak. This can be avoided in 2 ways:

1. Turn the steel coupler all the way down (when hot, or it breaks), so the block lifts itself inside, increasing pressure and avoiding leaks,

2. Not use cheap teflon couplers from China, because they are not the right size! This is counted in 5-10 microns.

A bowden tube not sufficiently down inside the teflon creates no leaks, but other problems.

Edited June 8, 2015 by Guest