Unique and Strange Issue on Ultimaker s3

[jshotts 0]

I am a part of Maker Space and am having issues with an Ultimaker s3. We're running firmware 8.1.1 and have the latest version of Cura installed. This space has two Ultimaker3 Extendeds and we are accostemed to troubleshooting issues. We are having a unique issue which we think has to do with temperature.

 

Essentially prints will start but they will have issues with under extrusion midway through their first layer.

 

Some clues are that the printer takes a long time to heat up and cool down. We have received an error a couple times saying that the temperature cannot be reached. It also seems to take a long time to cool down after we abort the print. We also have had the filament jam in the boden tube when it retracts after printing or when we try to unload it and use a differant filament. The filament seems to expand inside the printcore and then is too large to fit back inside of the boden tube.

 

We have replaced the printcore multiple times and eliminated that as an issue. We have replaced the filament multiple times and eliminated that as an issue. The contact points for the printcore seem to be fine as well. We also checked the second printcore in the head and that seemed to be working fine. All of the settings in Cura are standard and we have tried multiple different prints, and tried increasing the temperature as well. We just went up to 215c and it didn't seem to change the results.

[IRobertI 516]

Everything except the problem with not reaching temperature points to a broken or obstructed fan in the lid of the print head. The fan should spin as soon as either printcore goes above 40C.

[Dustin 55]

Yea sounds like the front fan is either obstructed, or not spinning up to the corrects speed.
I would recommend replacing this fan.