UM3, extrusion issue, as in no extrusion

[p25486 0]

Woe is me.

I have a new UM3. I did a couple prints out of the box in PLA. All looks good.

But, I was having trouble connecting to the WiFi, so I was printing with a USB stick.

I made an effort to get the WiFi working, but the WiFi connection wizard seemed to get stuck, no hot spot. So, I got frustrated and did a factory reset. Unfortunately, the printer forgets that it has filament installed when you do a factory reset (To Ultimaker: I suggest that you add un-loading the filament prior to the reset in future firmware updates! Or, make it clearer that this needs to happen prior to a reset.)

When I powered it back up, it started the start up wizard. When I got to the filament loading portion, there was already filament in the printer. It tried to push the old filament through, but obviously could not.

I feared that the knurled wheel had chewed a mouse bite in the filament. But, I tried to print anyway. No extrusion. :(

I unloaded the filament, and reloaded it with new filament (no mouse bites). But, still nothing.

Did I break the printer?

Do I need to clean the knurled wheel? How do I do that?

Help!

[gr5 2,210]

I haven't opened the feeder in a long time and forget the details but I think you just start removing screws.

Before taking the feeder apart, heat the core to 180C ( plenty hot to melt PLA) and push on the filament while holding the release lever on the feeder to make sure there isn't a problem in the head. No need to clean the feeder if the problem is in the head.

You have to push quite hard (10 pounds or 5kg force) but you should get some melted ooze if you push.

There was another post today I think by iRoberti I think. Or maybe ultiarjan. That linked to how to take the feeder apart.