Troubleshooting Your Thing-O-Matic

This troubleshooting page is for the MakerBot Thing-O-Matic. For help with The Replicator, go to The Replicator Troubleshooting page on

Table of Contents

Basic Rules

  1. Don't panic. Nothing is ever FUBAR.
  2. Sleep on it. Frustration will only compound mistakes.
  3. Persistence and patience debugs all things.
  4. You are not alone. Others can help you.


Here is the basic method for testing your bot to make sure that you're OK to print.

  1. Turn on the PSU.
  2. Connect in ReplicatorG

You should see a message like this:

[17:12:00] Motherboard firmware v2.8 ( Thing-O-Matic )
[17:12:00] Toolhead 0: Extruder controller firmware v2.8 (Extruder)

If you see a line like this:

 Toolhead 0: Not found.
Make sure the toolhead is connected, the power supply is plugged in and turned on, and the power switch on the motherboard is on.

Then you have a problem. Go to the electronics section for troubleshooting advice.
  1. Open up the Control panel.
  2. Jog the axes around; make sure that they move the correct direction and distance.
  3. Test the endstops. Make sure that they stop the correct axis and direction.
  4. Now let's move on to the extruder. First, look at the current temperature. Is this something reasonable? (around 20-30 C)?
  5. If this is OK, try heating your hot end — enter 225 as your target temperature and watch to see if the temperature rises.
  6. Do these last two steps for the heated platform as well, but use 120 as your target temperature there.
  7. If this is all working, do a test extrusion at the proper speed for your extruder. This should be 255 for DC motor-based extruders, and 1.98 for a stepper-based extruder like the Stepstruder MK6.
  8. If this works, then you've tested all of your axes and your extruder — try a test print!

Another way to verify if a part is good is to test the electrical circuitry. This only works for a handful of parts on the Thing-O-Matic, but it can be helpful in diagnosing your current problems. You will need a multimeter to test the below values:

Component Sub-Component Resistance (Ω)
Wires ≈ 0.02
Heater Cartridge ≈ 3-5
Thermostat (Room Temp.) ≈ 0.02
Thermocouple ≈ 20-22
NEMA Motors Red to Gray Leads ≈ 30
Green to Yellow Leads ≈ 30
Heater Board +12V to HEAT Pins ≈ 2
SIG to 5V Pins ≈ 4.6k
5V to GND Pins ≈ 115k
SIG to GND Pins ≈ 115k
MOT to MOTOR - Pins ≈ 0.02


Read the instructions.

Having trouble with a certain step? Do you think you are missing a part? Take care to check which build instructions you are reading. Start here for Thing-O-Matic or here for the Cupcake CNC. If you're building a Thing-O-Matic, make sure that you're building the right Plastruder for your bot, MK5 or MK6 and also keep track of which of the X-axis options you've chosen.
Is there something missing in the instructions? Drop us a message to update the guide.

Quick test: did you notice that the left side of the Y-axis doesn't use linear bearings? If you missed that, read over the instructions one more time, carefully.

Sanding parts.

You shouldn't have to force any parts — ever. When in doubt, grab some sandpaper or a file and get to work. Usually, just a few passes will make things go together much more smoothly.

If you begin to wonder if the parts you're working on go together, double-check the instructions.

X/Y Axes Alignment

Check to make sure that you have aligned your Self-Aligning Bearings. The X- and Y-axes should slide with only a little effort — it's best if they slide when the bot is tilted. Check out this video about bearing alignment.

Belts should not have slack, but they also shouldn't be so tight that you can't press them together with your fingers. If your X-stage belt is too tight, you may need to slit the belt between the clamps. There's a demonstration starting at about 2:07 in this youtube video.

Tape your nuts!

This is an old chestnut for the T-slot construction used throughout the MakerBot kits: tape in the m3 nuts. This is especially useful if you think that you're going to be disassembling part of your bot. For example, it's almost always a good idea to tape the nuts that hold on the bottom of your Thing-O-Matic, because it's good to be able to get to the electronics easily.


"I'm having trouble connecting to my Motherboard. I continue to get the 'Null version reported!' error."

Most communication errors can be solved by repatching power and data connections and making sure you are using the latest firmware for both Motherboard Stack and Extruder Controller.

Some customers find they have more luck connecting to their MakerBot control boards by downloading the FTDI drivers directly from the manufacturer. (Particularly customers running Windows XP.)

Connect to the Internet while using ReplicatorG right before updating board firmware

ReplicatorG needs to connect to the Internet to download the latest firmware for uploading to your bot. Don't skip over the Thing-O-Matic Firmware Installation section of the instructions — you want to make sure that your control boards are already running the latest firmware before you attach them to your MakerBot.

Calibrate your Stepper Driver Boards

The Thing-O-Matic Calibration stage has a number of important features, not the least of which are instructions how to use a multimeter to tune the REF settings of your Stepper Driver Boards. Should you overlook this stage, your stepper motors will run using undesired settings (you may notice loud "struggling" noise or other sounds) that at worst can overheat to create damage to themselves, the operator, or the bot as a whole.

"My Thermocouple / Heater Board Thermistor reads '1024'"

1024 is a built in error message coded into the toolhead firmware that means "this sensor is not connected correctly." First thing to check is whether your thermocouple/thermistor is patched correctly into your Extruder Controller (check the Electronics Installation page) for cable routing diagrams). The Heater Board plug can easily be pulled out of the A6 port of a Gen4 Extruder Controller when closing your bot — check carefully for that one!

Once you have your boards correctly re-patched, make sure to reset the boards and close and re-open ReplicatorG before testing again for a 1024 message. In particular, the thermistor will always return 1024 until the toolhead is *booted* with the thermistor plugged into port A6 the correct way!

No matter what I do, I cannot get my Power Supply Unit to turn on!

Check the brand of power supply included with your kit. If you have a Sparkle or a Coolermaster, then you will need to make sure that a jumper is soldered across two of the pins on the back of your MakerBot Motherboard so that the board provides a strong enough voltage trigger back to the PSU to kick it into life. The details are listed here.


"Where do I get the software I need to run my bot/slice my models?"

We use ReplicatorG as the application to control your MakerBot. Included within this software are the Skeinforge scripts that you will use to translate your STL model into a linear toolpath for printing, written as G-code.

"What software can I use to create models?"

You need a solid, manifold (“watertight”) STL-formatted file for importing into ReplicatorG. Many if not all solid CAD tools offer an .STL export option. If your tool doesn't offer this, then you can search for 3rd party export plugins or use MeshLab and similar 3D swiss army knife tools to open and convert dozens of file formats into an STL file.

For design software, start here. There are a host of powerful free and open source design tools available. Favorites include, Sketchup, OpenSCAD, Wings3D, and Blender. We have heard about but not experimented much with FreeCAD, HeeksCAD, POVray and Art of Illusion — apps that have serious fans in the 3D printing world.

For commercial solid CAD apps: Rhino, Autodesk Autocad and Inventor, Creo, and SolidWorks are expensive industry standard options, while Alibre Personal Edition, Cheetah, and bonzai3D are more affordable (but capable) modeling/CAD tools.

Where can I get models?

There are a number of places online that allow you to search for and download printable models. The best option is to visit where MakerBot Operators share and download MakerBot printable objects as well as other projects, models, and files.

"I'm uploading a model to my SD card — why is this taking so long?"

The data transfer speed to your bot's SD card is infernally slow. This is why most of us at the BotCave will go ahead and eject the SD card from the bot and copy the .s3g files for printing directly from a computer. How you do this is to generate the G-code for your print, double-check that the z-height maximum in the Homing section of the G-code is correct, and then click the button "Build to File."

The resulting .s3g file can be dragged from wherever you have saved it directly to your SD card attached to your computer. Then eject the SD card, re-insert it into your bot, and use the ReplicatorG command "Build from SD card" to print your item.

It might help to create an S3G folder on your computer so that you can quickly load your favorite models to your SD card for using the "Build from SD Card" button or selecting with your Gen4 Interface Board Kit.

"My copy of ReplicatorG is not behaving as described elsewhere in the wiki — cannot generate G-code or gives file access errors."

Are you running the application from a disk image (mac) or unextracted zip file (pc)? Investigate how you can create a local copy of the entire contents of the ReplicatorG file, not just the or executable file. The other folders include the drivers, example files, and other references that you will need to print and tune your bot.


I just started my first print, and my toolhead started printing above the platform!

You've skipped a very important step: setting your Z-height. Make sure to measure your bot's Z-height with a script, and then insert it into the line like this in the proper start.gcode:

G92 Z80 ( ---=== Set Z axis maximum ===--- )

Change Z80 to ZWhatever you measured. If you don't want to add that to the start.gcode, you can also add that into your gcode for each item you print. [WHERE?] Either way works.

One of my Thing-O-Matic's X, Y, or Z axes is moving twice as far as I want it to!

It sounds like one of your stepper driver boards might have switched to 1/4 stepping from our default 1/8 stepping. If your bot is brand new, get in touch with us about this. If it's been in service for awhile (more than a month of printing) then your board may have been damaged by static electricrity or hard use, and we won't be able to send you a free replacement. However, all is not lost: you can adjust your configuration and you'll be back up and running.

Open the thingomatic.xml file in the "machines" folder in replicatorg. Find the entry for the driver that you're using. That will look something like this:

<name>Thingomatic w/ ABP and Stepstruder MK6</name>

Now let's make one small change to the line in question for the affected axis. For example if it's your X axis, it'll be this line:
<axis id="x" length="106" maxfeedrate="4000" stepspermm="47.069852" endstops="min"/>  <!-- Pulley dia: 10.82mm / 1/8 step = 1/(10.82 * pi / 1600) -->

In this case, we're going to cut that stepspermm number in half, changing it from 47.069852 to 23.534926. If this were the Z-axis, the numbers would be slightly different, but you'd still divide it in half.

My model will not stick to the platform

No problem! Most likely your Z-height is just a bit too high. Once again find this line in your start.gcode:

G92 Z80 ( ---=== Set Z axis maximum ===--- )

And then increase it by about .2 mm. You can also do this in the gcode you've generated for printing — this is actually a good way to test. Keep in mind that the MakerBot's lasercut plywood will change shape just slightly with temperature and humidity conditions.

The corners of the raft curl up, or the part curls.

When building on a raft, the first line segment is the most critical point of time during the build. If the first line segment adheres nicely to the build area, you're pretty much guaranteed that the rest of the build will go smoothly (if your object is buildable). On larger parts, if the first and last segments of the raft are too loose, the part will warp and peel off much sooner than if they were flatter.

To control this, you'll need to readjust your Z-height. This is how to do it on a Thing-O-Matic.


On a Cupcake, you can adjust the Z stage height while it is building the raft to fine tune it and get it exactly right. Do this by turning the Z pulley or moving the Z belt (or build a crank or knobfor this).

In this image, note from the left)

  • The second and third loops are way too loose, and are nearly lifting off the build platform already; If the entire part is built this way, it may slip off the platform during build, or warp and peel off, or the first few layers may be too loose and not adhere to each other.
  • The next several loops are too flat and are overlapping; if things are left this way too long the pressure in the nozzle will build up and the filament will strip and jam. Even if it doesn't jam, a raft this thin will be difficult to remove from the platform.
  • The loops on the right are just about perfect — somewhat flattened, but not overlapping.

Working without a raft

Curl is tricky, says Emmett in a forum post, and gives these suggestions. A heated build platform (HBP) will be a help. If the plastic is curling off of the build platform,

  • Make sure the build platform is as level and sticky as possible (kapton tape makes a great surface, especially if cleaned with rubbing alcohol).
  • It can help to blow on the print for the first few layers; it can help break the warpage cycle. You shouldn't have to [blow] any more once the corners have stopped curling.
  • Failing that, you might need to change the temp settings of your nozzle and HBP.

Foxdewayne adds

  • You are probably not smashing your first layer down onto the platform hard enough. You want a nice wide extrusion. (However, making it too thin and flat causes other issues as mentioned above)
  • Another thing you can try is to sand your platform so that it is rough.
  • I highly recommend that you get a heated bed and you will have little trouble with curling, and wont even need a raft.

For more answers, check the forum.

I've set my z-height, but I'm tearing up my platform

OK, no problem! Just reduce that number by .2 or .3mm, the opposite of the above item.

I tore up my Automated Build Platform belt or it's really warped from printing so many awesome things!

Don't worry! You can get replacements in the store or you can make your own belt like this or this.

How do I change my filament?

To remove the current filament and start a new filament feed, first heat the chamber of the hotend to 220 degrees Celsius so that you can easily pull the filament back out of the chamber. If you have just completed a print, the chamber might be warm enough for quick removal, otherwise open the Control Panel to manually set the hotend to 220 - 225 degrees Celsius.

Additionally, for 3mm MK5 and MK6 toolheads, you will want to loosen the bolt pressing the Delrin plunger against the filament. The MK6 toolhead with 1.75mm plates does not have a plunger.

Pull out the filament by hand or set the extruder motor to reverse to advance the filament back out of the thermal chamber. Next, insert the new filament and drive it forward into the thermal chamber, pre-heated to 225 degrees Celsius.

If you are changing colors, it might be a good practice to print a noodle of filament for long enough for the color to shift from previous color to the new color.

Extrusion problems

  • The plastic isn't going into the extruder. I can hear the motor turning, but nothing comes out!

Software and firmware problems

General printing problems

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