RE: constant under extrusion
This I am confident that this video should solve your problem. I know because this was the exact problem that I had when I got my mini. The first print was fine but the ones after were under extruding like crazy to the point where the first layer wouldn't even print and when it did it looked splotchy like a pearl necklace. The Video!
Yup, we did that fix (talked through it by Prusa's online chat); my heater block was also about 5mm too low. That helped, but I was still getting jams. Those were down to a problem with the connectors of the PTFE tube.
The one thing I'd use caution doing is the two-spanner tightening of the PTFT tube nuts at each end; too much torque and you'll compress the olive, which in turn restricts the PTFE tube. Unless anyone can give me a really good reason to do otherwise, mine are staying finger-tight rather than spanner-tight (or my usual default, gorilla-tight).
Getting a pretty perfect treefrog printed right now. Makes me wish I had green or orange filament 🙂
RE: constant under extrusion
Dear Richard D,
Glad you found your fix! I never knew that overtightening the olive would cause it to constrict hehe. I always thought that it would make it slide downwards on the PTFE tube.
-TheMadCadder
RE: constant under extrusion
@richard-d
where did you get the mini USB relocation kit? or what are the details? TIA!