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Mintemp error bed

#12207 (MINI)

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MINI
MINI+
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What happened?

The printer will display "Mintemp error" for the heatbed if the printer's heatbed temperature goes below 15 ºC at any point. In this case, the printer will stop the heating and display the message on the screen. The printer then waits for the user to inspect all parts and if needed fix the issue.

Error name: Mintemp error bed

Error code: #12207

How to fix it?

The error might indicate some issue with the wiring, either the heater or the thermistor cables are possibly damaged.

When running the self-test you must have the flexible steel sheet placed on the magnetic heatbed. Without it, the self-test can fail and give you the Mintemp bed error.

A visual inspection

Check the heatbed, where the thermistor and heater resides, that no wires have broken off the sensor or heater themselves. While the printer is turned off, carefully try to move the wires by hand. If any of them have come detached your search is over and the part needs to be changed. It is not recommended to solder these wires, moreover, for the thermistor, it will change its resistance and thus readings. Spare parts can be found in our e-shop, or you can contact Support for assistance.

Try preheating the heatbed in LCD-menu -> Settings -> Temperatures -> Heatbed to 90 ºC. After the temperature is reached, move the cables behind the heatbed by hand to see if the error will appear. In case the LCD main screen shows 0/0 in the heatbed temperature, check the cable connections to the Buddy board.

Loosen the one screw securing the cover (circled in the picture below), remove the top cable cover and flip it open to reveal the board.

Check that all the connectors are secure in their sockets, according to the picture below. Focus on the thermistor and heater cables (yellow arrows). Though unlikely, rough shipping or handling could have shaken the heater or thermistor cables loose.

Checking the resistance

The table below describes the correct resistance for each part, as well as what scale you should set your meter to. We have another more in-depth guide on Multimeter usage. All thermistors are rated to be 100 kΩ at 25 °C. To be realistic, with a varying temperature between 20 °C and 30 °C, you can expect a wider range of readings (~85-125 kΩ) than with the heater.

There can be micro-fractures in the cable, breaking the connections only at certain positions. Therefore, try to move the cable a bit while doing the measurement and see if the value changes drastically.
Part
Resistance
Multimeter scale

Thermistors (Bed and hotend)

[80 kΩ - 125 kΩ]

200 kΩ

Heatbed

[6.5 Ω - 7 Ω ]

200 Ω

The part should be cold (room temperature) and unplugged when measuring the resistance!

Where to measure

For every component, there are several options, our main focus will be on the connectors. The measurement appears on the multimeter LCD as soon as the measurement probes touch the component. To obtain the correct and relevant values, this is where you need to apply the probes:

  • Thermistors: metal inserts in plastic connectors

  • Heater cables: screws holding the cables in the connector

The hot end and heat bed have the same connector. Make sure you measure the correct one.

Parts replacement guide(s)

In case you find some parts are faulty, please order them using our e-shop, then follow the service guide(s):

How to replace a heatbed thermistor (MINI/MINI+)

How to replace a heatbed (MINI/MINI+)

 

8 comments

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L Wo
•
Hi Prusa, can I ask why you designed your printers to not heat themselves up if the room is below 15 degrees? Now I have to heat the room that the printer is in? Just turn on the heat bed and print head?! Can I bypass this error?
This seems like an issue that doesn't need to exist
Reply
tsegner
•
I have this issue. Followed the instructions, and located a bad wire. Tech support wants me to 'shoot a video'?!?! explaining how it happened and why it's not my fault?! WTF Prusa?
Reply
Levi
•
Just to add to this, make sure your printer is warm enough before going too far into these repairs. I received this error simply because the room was too cold. I warmed the parts to above 15C with a heat lamp and my problem was solved.
Reply
Paul
•
I just started getting this error with all prints.  If I do first layer calibration the nozzle and bed heat up but then it crashes, reboots, and then shows this error.  I looked at the wires and didn't see any issues.  Any idea what is going on?
Reply
Paul
•
FYI-- all self tests have passed with no issues.
Reply
Paul
•
It looks like the issue was with the connector to the heatbed.  When the bed got into a certain postion this error happened.  I took off the part that holds the cables tighter and now it seems to work.
Reply
Jackie
•
I'm receiving this error after only 3 months of receiving this printer.  I do not see any loose cables.  I'm just someone who uses this machine for fun and I am not mechanically or electrically inclined to try and figure out this using a Meter as in the instructions.  I am very disappointed that no one has contacted me back after I sent a message to Prusa.  Should I just throw this printer out?
Reply
David
•
Hi Jackie! Sounds like your heater or a thermistor might be faulty or have a cable twisted off. Are you sure the Prusa support did not get back to you? Try using the "live chat now" window at the shop.prusa3D.com, you will get an instant reply :)
Reply