I have gone through 3 blade assemblies now and I have become an expert and identifying the cause and result of this one issue.
Indicators to this issue:
# Noise of machine changes from spinning to a “free spinning” sound which is significantly louder
# plastic burning smell emitted
# Chunks of plastic remain in the engine base docking area.
# Brown liquid in the base area
# If all of these are happening then the cause is that your blade was probably submerged in water at some time with heat. This has popped the seal on the bearing case and the lubricant has leaked and now the bearing is rusting and can’t handle the heat being generated from the speed of rotation.
# The test is to blend a water only smoothie and see if the water changes colour to a dirty brown, if so the bearing seal is gone and the water + rust is leeching into the smoothie.
Stop use immediately buy a new blade assembly.
Learnings:
don’t put the blade in the dishwasher - the rapid heating and cooling breaches the bearing seal.
don’t submerge or leave submerged the blade assembly
Verdict - the blade assembly is not a well constructed part considering it’s high speed use and need for bearing integrity. It is very susceptible to damage and water ingress.
That’s what I’ve found