Update 2: tl;dr: had to turn off (or maybe tune) z contouring.
So after looking at it and pulling it apart and several times missing the window to go look as its happening, it looks like it wasnt extruding enough to actually stick, eventually there is enough of a ball that it sticks and it repeats causing that pattern.
I literally just found out after idk how many years of 3d printing that the post slice view can be switched to visualize different things including flow which coloured specifically those areas blue or really low, like down to 0.1 even. Going through everything one by one to make it consistent flow, it turned out to be 'z contouring' was on and presumably very misconfigured. I still cant believe it wasnct the broken extruder. I even threw the bmg clone and calibrated it to get the same results as the repaired pap lite.
Update: Shockingly the broken extruder that was somehow still extruding wasn't the cause. I printed another a4t shell and the same areas have that defect. It seems to occur mainly on just the exterior wall of both inward and outward overhangs but parts of the same section dont have it, and this model is the only one I've seen this on. I'm waiting for the printer to heatsoak for further testing but at 3 teardowns in, I'm just guessing now.
Edit: It was the extruder. One of the belt gears sheared off, and there was enough friction between the pieces that it still worked at slower speed, even well enough for the calibration test prints I tried. I had spares that I printed ages ago and now it works.
I started getting this weird exterior wall defect that I haven't seen before. Calibration testers come out clean though and it's driving me insane.
Using orca slicer with an e3 switchwire trying to print parts for my other printer so I can rebuild this one into something not a switchwire.
