(Solved) Extruding gaps / sticking issues / extruder clicking sound
Suddenly had quality issues - plastic not sticking in some parts of the bed, corners lifting. Multiple calibration attempts and bed adjustments did not help.
Suspect - Bed sticking issues / bed shape change etc / filament issues.
Next week heard loud licking noise from extruder motor, observed that it happens at similar locations. Carefully watched nozzle as it is extruding plastic and found that it is stoping extruding at the same points.
Suspect - extruder is clogged or file problems.
While checking for clogged extruder, removed filament and run empty "load filament", found out that extruder motor is making the same clicking sound, motor erratically moves back and forth.
Issue found - extruder motor connection or interference.
Removed wrapping of extruder cables, wiggled cables and checked motor again, no problems anymore. Rearranged cables, wrapped them back, checked extruder motor in all head positions, no issues anymore. Just finished perfect 12 hour print job.
Learning: before disassembling extruder or starting to check cables for breaks (how to do this without disassembling motor ?!), check the cable management for interference.