TAZ Z-Axis Stuck Stepper motors and Rattling

Let me share my latest TAZ6 adventure but first here are my printer stats taken from the “About” screen on my printer.

I have a total of 50d 21h 13m 38s of print time (call it 51 days of printing or 1,224 hours.

Total print count 552 and I have completed 507 for a success-ish rate 93%. A completed print does not mean a successful print.

The longest job (print) was 21h 3m

Extruded 1643.6 m of filament.

Early on, I had challenges with cheap/crappy filament, not knowing what I doing (learning the printer do’s and don’ts) and then a thermistor on the hot end not reading correctly that came with the TAZ6. Replaced the thermistor and life’s been mostly good in TAZ6 land.

Done boring you with non-essential information, let’s get to the challenge.

1/3 of the way through a 13 hour print the z-axis step motor stopped doing their job. I did discover the problem about half way through and stopped the print. I was having the same symptoms as “CallDrop” in this thread (see the video they posted):
TAZ 6 - problem with Z axis --- HELP

Troubleshooting steps:

  1. Verified frame was square – it was.

  2. Verified left and right worm thread height to bearings were equal – there where.

  3. Try to isolate whether the challenge was one or both z axis stepper motors, cables, connectors, or the Rambo 1.3L board with the following steps:

a. Removed connectors at both z step motors. Then removed connector on the x-axis step motor.

b. Clipped associated tie wrap and connected left side z-axis motor connector to x-axis step motor. Operated the TAZ movement in the z axis and got the crazy rattling on the x-axis step motor.

Thus, z-axis step motors are probably good.

c. Opened up electronics, clipped tie wraps as required and connected the left side z-axis connector (remember the other side is connected to x-axis motor) to the x-axis socket on the board. X-axis worked well.

Conclusion, problem is probably not the cable, connector or z-axis motors but the Rambo 1.3L board.

Board on order (no warranty).


I was doing some napkin calculations. Please check your spreadsheet. I think you might be off by 15mm of extruded filament. If you change the 13 minutes to 31 then its within range. This could also be an error over inconsistent diameter though.

Umm… First sentence from my post: “my printer stats taken from the “About” screen on my printer.”

Here’s a screen shot…

The following is my courtesy update and documentation for the next board failure owner.

I purchased my replacement board a Rambo 1.3L from a reseller in California (fast and efficient). The board was identical less two sets of connector header pins at X1 and X30. I was not able to fully de-solder the connector pins on my failed board so I took a couple of loose resistors I had, formed a “U” with the pins and installed into the empty circuit holes and soldered into place. Clipped the leads to length and set the distance apart as required – it works. I suppose the board sold directly by Lulzbot comes with these two pin headers in place.

Before I removed my old board I labeled all the cables, took pictures and documented on a circuit board image I printed from the internet. This was helpful to ensure I got everything back in place. Folded up the paper and put it in the electronics enclosure when I was done with the install.

Now, let me shoot and compliment Lulzbot designers or whoever led the design effort on the printer.

I just happen to be a DFM DFMA engineering consultant and trainer (last 20 years) and before that 22 years design engineering (google DFM DFA Training if want to know who I am). I’ve looked at the work instructions available on line and examined the TAZ6 for several years and worked on it. I consider the printer to be reliable and robust however on a scale 1 to 10 I rate the manufacturability to be a 3. Lulzbot is spending at LEAST 2X more than they should on assembling this thing. The Rambo install is actually about a 2 as one will need tweezers, special socket drivers, small hands and the end product quite honestly looks a pile of mating snakes seriously; step up your game for the money and professionalism.

See pictures below.

Anyway, I finally got the board in, plugged in my computer and was able to flash the board and I’m back to printing for my customers and grandchildren.