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Ultimaker Original not working

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Hey all,

Im having problems with my Ultimaker and I can't pinpoint the problem.

The error I get is a MINTEMP error on the Ulticontroller followed by a machine reset.

It happens when the thermocouple is touching anything. If it is outside the Aluminum block, it will read temperature right and no error. But once it touches the block, or I touch the cord with 2 fingers (not 1), we go right to a MINTEMP and then it resets.

I have:

- Checked all connections and used multimeter to ensure that they are working

- Flipped the yellow & red wires

- Replaced the thermocouple

- Yelled at it

Anyone have any ideas?


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Sounds like some sort of grounding/shorting problem... Have you checked the heater cartridge... does the wiring on it look ok? What happens if you remove the heater cartridge from the block before you insert the thermocouple. Does the thermocouple still freak out?


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I agree, it seems like a grounding problem.

The heat cartridge looks fine. Removing it minimizes freakouts (there was only 1 MINTEMP in ~10 trials after I removed the block, as opposed to a 100% freakout rate).

Another thing I noticed, I don't get errors when the ultimaker is on its side with the electronics exposed. I followed up a bit and found that if the white cables touch each other in the first 10 cm of cable leaving the board, I get an error


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This one seems new to me. I don't think I"ve heard about this particular exact problem.

Just a little explanation of how it should be working:

The thermocouple goes up to a tiny circuit board on the print head. That board should be powered up (you can test it). The output signal from that board is a voltage from 0V to 5V where 5V is 500C and 0V is 0C and it's linear in between. So at room temp it should be around 20C and 200mv.

Did you check those voltages there and also at the PCB under the UM?

In the past people have reported problems where the temp is very sensitive to other wires near the thermocouple - before it gets to the tiny PCB on the print head. So keep those wires at least 1 cm away from the fan and heater wires. But once the voltage leaves the print head it tends not to be sensitive to noise but of course the wire can break and that's another common problem.

So I'm surprised there would be an issue on the underside.


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Yup, I checked the voltages. 'twas all good. I guess it was a wire proximity issue, the whole issue went away when I unplugged the fan.

The fact that unplugging the fan fixed the problem boggled my mind beyond measure. I still haven't quite recovered :-/


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For the ones getting a MINTEMP error - it can be due to a loose connector to the TC board.

After a while the strains on the cable this connector can break.

I fixed this by removing the connector and soldering the wires directly to the board.

What you can also do is order a new connector and use crimp sockets to attach it to the wires. The connector you need is a Micro JST XH 2.54mm 3-pin T-1 plug which you can usually find on ebay. I had mine shipped from Hong Kong for a few cents each.



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