This is a Vitamix model VM0103 blender. The motor runs jerky start and stop in the low to
near high end of the potentiometer range. As I read the ohms from the potentiometer everything seems smooth there are no dead spots. The brushes themselves look great and long. Do you think this carbon build up on the armature could be causing the problem and if so what would you use to clean that?

 

Seems healthy-like new to me. Check connectors/terminals firmness to the control board.

 

Measure the resistance between the brush and the winding on the rotor.

 

Measure the resistance between the brush and the winding on the rotor.

Do you mean brush lug to brush lug through the armature?

 

I see what I think is the start of a serious problem, in that first photo. I see one segment with what looks like a worn off carbon area on the leading edge. One loose segment can cause serious problems at higher speeds. And a bouncing brush will certainly disrupt a speed controller circuit.


I speak from very recent personal observation. I was presented with a very high performance leaf blower/vacuum, having the complaint that "It Lights up inside". Certainly the brush sparking was very intense almost all around the commutator, and the brushes were mostly ground down. And it was only just out of warranty.
The problem is one loose commutator segment, risen up several thousandths of an inch. I can press it down with my thumb, but it pops back up.
This was a high power motor, marked as 9 amps at 120 volts AC at 15,000 RPM. (that is no misprint!)

So for the TS, if the blender is still under warranty, return it! If not, re-seating the segment with some adhesive might be possible. That is my hope with my problem motor. But what sort of adhesive will last in that application.

I do not want to hijack the thread, but any solution for the TS problem that I see will also benefit me.

Try this with the blender unplugged!
Probably the commutator should be very carefully examined, and slowly rotated with a finger feeling for any unevenness. If the TS is fortunate, what I see is just alighting issue.

 

Hello all, thank you very much for the replies. I broke the heads off the rivets on the potentiometer and cleaned the wipers and everything else inside. All is working well. Thank you again.

 

I would return it anyway if has warranty and buy a brand without that flaw on the control board.
Decades ago, at my workplace, had to implement applying silver ink at the production line to those riveted track contacts on Alps brand fader potentiometers before assembling as they were failing shortly after. The supplier could not fix their product reliably and we were buying thousands of them.
If has no warranty, and you have silver ink, apply to ensure conduction track-to-rivet.

 

I would return it anyway if has warranty and buy a brand without that flaw on the control board.
Decades ago, at my workplace, had to implement applying silver ink at the production line to those riveted track contacts on Alps brand fader potentiometers before assembling as they were failing shortly after. The supplier could not fix their product reliably and we were buying thousands of them.
If has no warranty, and you have silver ink, apply to ensure conduction track-to-rivet.

Is silver ink a conductive grease?

 

Not grease at all. Dries as paint.
----> https://www.techinstro.com/silver-conductive-ink/
Several robbery levels depending on vendor chosen. Very small amount is applied , like two millimetres dot contacting/wetting both the track and rivet restore continuity.
----> https://search.brave.com/images?q=silver+conductive+ink&source=web
I believe keyboard circuits are ink printed, not copper etched. :

 

When brushes foul the rotor, try another brand of brush that fits.

 

OK, if it is not a motor problem but rather a speed controller problem, a much different issue.
And after the TS has repaired the variable control it is not likely that the appliance is returnable.