It shouldn't be twitching at all. That fan can't be controlled, it turns on automatically when the hotend is at 50C or more. If doesn't spin and twitch it might be damaged or have a bad connection. Could you check it?
First of all, pull the head to the front of the printer and look from the back. YOu can touch it to see. Is it possible it just appears to be twitching but in fact is spinning in a blur?
Twitching sounds like a broken fan to me. It does not have a speed control - just on/off and is not controlled with software but hardware I think (older UM2s just turn it on when power comes on). It's possible it's plugged into the wrong socket on the PCB. There are detailed assembly instructions for the UM2 somewhere on this website including where that cable goes. I think that fan is a 5V fan. I have some spares if you need one. Email me directly at thegr5store _at_ gmail.com. They aren't in my store but I have a few. They don't have any connectors on them so you would have to solder it onto the old connector.
You could put 5V across it to test the fan. I screwed up and put 7V or so and destroyed my fan in about 1/10 of a second.
First of all, pull the head to the front of the printer and look from the back. YOu can touch it to see. Is it possible it just appears to be twitching but in fact is spinning in a blur?
Twitching sounds like a broken fan to me. It does not have a speed control - just on/off and is not controlled with software but hardware I think (older UM2s just turn it on when power comes on). It's possible it's plugged into the wrong socket on the PCB. There are detailed assembly instructions for the UM2 somewhere on this website including where that cable goes. I think that fan is a 5V fan. I have some spares if you need one. Email me directly at thegr5store _at_ gmail.com. They aren't in my store but I have a few. They don't have any connectors on them so you would have to solder it onto the old connector.
You could put 5V across it to test the fan. I screwed up and put 7V or so and destroyed my fan in about 1/10 of a second.
I assume his fan is the new model (more silent) since he has a um2+ fancap. So it should stay off until heats up.
And indeed twitch is a bad symptom.
- 2 weeks later...
Thanks, everyone! It turns out that there was a small piece of filament that was keeping the fan blades from spinning. Once I pulled that out, the fan starting working, and the Ultimaker has been printing beautifully.
I appreciate your replies! Have a great day
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neotko 1,417
The part behind the head is a small fan. Indeed if doesn't work it can cause extrusion problrms, clogs and shorts the tfm coupler life span.
It might be just disconnect inside the black snake cable join, roll it up and inspect the cable plugs.
Also that fan only starts to spin as soon the head gets to 50C, so it will stay put until the heat up starts.
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gr5 2,224
It's almost always a problem just above or inside the print head where the fan connectors are. As neotko suggests.
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