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Hello fellow Ultimaker enthusiasts,


This week I was installing a new temperature probe and heater into my UM2.

When I took the control board down, I noticed some brownish areas around the microsteppers (thanks Shannon at 3DVerkstan support for the info!).

Also the capacitors at C60 and C64 appear to be burnt or scorched (small red circles)

Anybody else seen this? Tried to repair it?

If I look at the schematics on github, it looks like these are 4,7 uF capacitors, and my guess is that they are part of a voltage smoothing circuit.

The reason I ask is the replacement board is quite pricey, and since the printer has been in fairly heavy usage since 2015, might make sense to put that money towards a replacement machine rather than a new board...


Thank you for any comments or suggestions,



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I have the same brownish areas around the stepper drivers and the printer is still fine (I don't use it heavily though). As for the capacitors, this might be problematic. Never seen it on the boards I handled.

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Thanks Nicolinux for the quick reply


- brownish areas not worry about (Shannon did mention that was more common)

- capacitors, welll, i guess it doesn't hurt to try and replace them if I manage to do it right, might make the board stop working all together if i mess it up... 
The machine runs now, just increasingly difficult to keep tuned and get clean looking prints...


Thanks again,



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Silly question, why are your motor cables white?


The brownish we see on all board that have a long runtime. Nothing to worry about there. The burn around the C60 is strange, could have been a bad solder joint.


Both C60 and C64 aren't super critical components. And your board will most likely function fine without them. But might not pass EMC emission tests.

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Hi Daid,


Alright that is good news, if the capacitors are not that critical perhaps its better leave them.

Spent part of the night looking up how to test faulty capacitors in circuit boards, how to solder SMDs, etc... only worked with through-hole electronics in my past. If it isn't broken, do not fix it 🙂 


Probably should follow that advice more often. I've installed the bondtech extruder, matchless V3 block, fans (because the the labern shroud I put on filled up with plastic on an overnight print gone wrong), etc so in the pursuit of better prints my UM2 has been through some changes. The white motor leads are just some short extension cables I had from another project...


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