i3 Mk2.5 - Significant quality issues over time  

i3 Mk2.5 - Significant quality issues over time

EDIT - Please click to view the full size files.  They are slightly cut off in all directions in forum view.

Hey everyone -

I've begun to have some serious issues with print quality in the last few months out of my mk2.5.  It was originally a kit mk2, then 2S, now 2.5.  Everything HAS worked perfectly well before, but having run down the normal list of things to check, I'm finally hitting a brick wall when it comes to knowledge. 

Attached you'll find a variety of prints in PLA and PET showing a variety of surface defects - they seem to be the worst when the cooling fan is operating.

A list of things I have done in the effort to resolve these issues: Cleaned and lubed the rods, checked bearings for play and damage, all seem smooth.  Checked belts for appropriate tightness.  Verified pulley set screws are tight and there is no play or movement.  Disassembled the hot end, replaced the PTFE liner (my printer uses a genuine LITE 6, as the original V6 suffered a massive blob and broken heat brake long ago) replaced the nozzle.  Cleaned filament drive gears, adjusted tension.  Rebuilt y-axis and re-calibrated all axes. 

Print issues occur identically via SD card or over octoprint.  All prints are sliced in the latest version of PrusaSlicer using default settings for the 2.5 on 0.2mm layer heights. 

This is where I hope some outside perspective might get me pointing the right direction.