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Another Ultimaker 2 heated bed issue

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Hi,

Hopefully someone can clarify this for me.

I have recently got the TEMP SENSOR BED error. The first thing I did was check all the connections and leads going to the heated bed and to the motherboard. Everything was fine.

I then read about the issues with the soldering of the temp sensor attachment point to the heated bed. Seemed fine but I reheated the solder anyway. After checking everything I got my multimeter out, and with the heated bed completely disconnected from the machine, I measured a resistance of 108 Ohms. Falls perfectly in line with the 21 Degrees ambient temperature I have in the room.

Thinking everything was ok with the thermistor I reattached everything and switched the ultimaker back on. Going to the maintenance section where you manually set the temperature for the heated bed, whilst leaving it at 0 Degrees, I noticed the temperature reading was 24 Degrees. Not normal. At this point the ultimaker is still on and the TEMP SENSOR BED error is once again on the screen. I then measured the resistance again and the reading was around 175 Ohms (also not normal). The heated bed is at ambient temperature.

Also, if I heat the bed up the temperature shoots past the target temperature and then slowly comes back down. I then went up to 70 Degrees and the (measured) temperature rapidly hit 180 Degrees and then the error occurred again.

Reading other posts I have already decided to purchase a new PT100 thermistor. Does this all point to the thermistor being the problem though? Could it be anything else (mainboard)?  I have had the printer 1.5 years now and nothing has gone wrong up until this now. Hopefully the solution is as simple as soldering and sticking the new thermistor to the heated bed!

Just to recap: with the printer under power, resistance was measured at 175 Ohms (correct?). Without power it measured 108 Ohms. I haven’t measured the output voltage of the heated bed directly from the mainboard yet.

Thanks for all the help in advance!

Max

Update 10.11.2015:

I just tried some more things:

With the temp sensor cable unplugged I measure 108 Ohms.

With the temp sensor cable plugged in I measure 45 Ohms.

With the temp sensor cable plugged in and the ultimaker on I measure 175 Ohms. Display temp is 21 Degrees.

Is the control board malfunctioning?

Regards,

Max

Edited by Guest

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Going to the maintenance section where you manually set the temperature for the heated bed, whilst leaving it at 0 Degrees, I noticed the temperature reading was 24 Degrees. Not normal.

Maybe I miss the point but this seems perfectly normal to me....  assuming the ambient temperature of the room is 24 Celsius.

Did you check the PT100 separately? I mean just go into maintenance, to heat the bed (so you can read the temperature) leave it to zero and then heat it with an external source like a heardrier?

Ofcourse if you have a spare PT100 (like from the hot-end) you can also just stick it to the bed and test like this.

Edited by Guest

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Going to the maintenance section where you manually set the temperature for the heated bed, whilst leaving it at 0 Degrees, I noticed the temperature reading was 24 Degrees. Not normal.

Maybe I miss the point but this seems perfectly normal to me....  assuming the ambient temperature of the room is 24 Celsius.

Did you check the PT100 separately? I mean just go into maintenance, to heat the bed (so you can read the temperature) leave it to zero and then heat it with an external source like a heardrier?

Ofcourse if you have a spare PT100 (like from the hot-end) you can also just stick it to the bed and test like this.

 

That is exactly the problem. When the temperature sensor cable (going to temp3) is unplugged the resistance at all points (at the thermistor, on the block and at the end of the cable) all measure exactly 108 Ohms. This is correct for the 21 degrees i have in the room.

Today after trying some other things, like when the cable is attached to the electrical board, I measured 45 Ohms at the thermistor. Today when the ultimaker was switched on the display showed 21 Degrees (somedays it is 35 Degrees/24 Degrees, different every day). However, the resistance measured was 175 Ohms at the thermistor.

How can the thermistor be changing its resistance (at a constant room temperature) if it is connected to the electrical board?

I wanted to rule the heated bed out by attaching a new pt100 thermistor directly to the board but haven't got round to it yet.

Thanks for the help!

Max

Edited by Guest

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You might want to connect the bed to the temp sensor 2 and rebuild the firmware to change the pins. This way you could remove the board bed temp connector from the problems and see if it's the board or the bed?

 

Hi neotko,

I don't know how much you know about the firmware but that would mean switching the pin numbers from 10 to -1 wouldn't it? I just looked it up in the firmware and that's the change that would make sense.

It would be great if you or someone else could confirm this as there is very little information about what pin numbers correspond to what parts on the board! Hopefully this works!

Regards and thank you,

Max

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On the pins.h search on the board 72? I think it's 72 from memory...

Then change the pin numbers of one sensor to the other.

Edit:

Yes it's 72

 

#define TEMP_BED_PIN 10 // Bed#define TEMP_0_PIN 8 // Extruder 0#define TEMP_1_PIN 9 // Extruder 1

 

 

Change Bed pin 10 to 9 and  Temp_1_PIN 9 to 10

This should change the temperature sensor from the bed to the extruder 1 free sensor.

Edited by Guest

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You can't measure the resitance with the power on. You can't trust that measurement so ignore it.

The way a multimeter and the way the UM measure resistance is by putting some current through the temp sensor and measuring the voltage across it. If both instruments are putting current through the temp sensor it will get a higher voltage and both will read higher than intended. The multimeter puts much less current though (much more sophisticated instrument) and so the UM doesn't notice but the multimeter notices when the UM has power on.

The error you are getting only occurs if you have SEVERE errors in resistance such as 0 ohms or 1000 ohms. This can only happen if you have a short circuit or open. Short circuit is very unlikely. What's much more likely is a wire is just barely connected and moving the bed or touching the cable moves it to an open. The problem could be where the cable connects to the PCB but much more likely it is at one of two places: either the screw-down connector on the board or in the solder connection between the connector and board. I recommend you reheat all 4 solder connections and remove and re-insert the PT100 wiring.

The PT100 can indeed fail but the odds are 95% wiring problem, 4% PCB proglem, 1% PT100 problem (one person on the forum convinced me it was really their pt100 that was at fault - about 2 years ago).

https://ultimaker.com/en/community/view/5791-error-stopped-temp-sensor-bed-solved

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You can't measure the resitance with the power on.  You can't trust that measurement so ignore it.

The way a multimeter and the way the UM measure resistance is by putting some current through the temp sensor and measuring the voltage across it.  If both instruments are putting current through the temp sensor it will get a higher voltage and both will read higher than intended.  The multimeter puts much less current though (much more sophisticated instrument) and so the UM doesn't notice but the multimeter notices when the UM has power on.

The error you are getting only occurs if you have SEVERE errors in resistance such as 0 ohms or 1000 ohms.  This can only happen if you have a short circuit or open.  Short circuit is very unlikely.  What's much more likely is a wire is just barely connected and moving the bed or touching the cable moves it to an open.  The problem could be where the cable connects to the PCB but much more likely it is at one of two places: either the screw-down connector on the board or in the solder connection between the connector and board.  I recommend you reheat all 4 solder connections and remove and re-insert the PT100 wiring.

The PT100 can indeed fail but the odds are 95% wiring problem, 4% PCB proglem, 1% PT100 problem (one person on the forum convinced me it was really their pt100 that was at fault - about 2 years ago).

https://ultimaker.com/en/community/view/5791-error-stopped-temp-sensor-bed-solved

 

Hi gr5,

Thanks for the info! The resistance of the thermistor always measures 108 Ohms at 21 Degrees which is fine! I also tried the solution proposed by neotko (recompiling the firmware to use temp2 instead of temp3) and i am still getting the same strange behaviour!

I have already reheated the connection of the temp sensor to the board but i will do as you suggested and give all the connections a work over!

What do you mean by "remove and re-insert the PT100 wiring"?

Thank you!

Regards,

Max

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Just one other thing, the wire's going into the connector at the heated bed, are they blank wire or do they have solder on them? If they have solder on them cut it of and fix again with the blank wire.

I did not do it (just tightened the connector) and got the error again after a few weeks.

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Just one other thing, the wire's going into the connector at the heated bed, are they blank wire or do they have solder on them? If they have solder on them cut it of and fix again with the blank wire.

I did not do it (just tightened the connector) and got the error again after a few weeks.

Yes they did! It was one of the first things I did to try and correct the problem. Thanks for the tip though!

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Hi everyone!

After re-heating all the solder points on the heated bed a few times, also adding more solder on some parts as i went, everything seems to be stable now.

The only thing that has changed is at ambient room temperature (21 degrees) the ultimaker is showing a bed temp of 28 degrees. The resistance of 109.2 Ohms would seem to confirm that but something must of happend whilst soldering.

Is there anyway to adjust for the change in resistance in the firmware? I have looked at the PID values but i don't think that is a solution.

Regards,

Max

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your bed is probably always about 7 degrees cooler than you think then so that when you ask for 60C you probably get 53C.

I would disconnect the wiring underneath the UM2 and measure it there then measure it at the actual part - the tiny PT100 and at every junction in between to see if the PT100 is now damaged and reads 109 or if one of the many connections has 1 ohm resistance somewhere along the path.

Or alternatively change the default PLA bed temp to 67C.

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What do you mean by "remove and re-insert the PT100 wiring"?

 

I meant in the terminal block on the heated bed plate - unscrew the 2 screws, remove the 2 wires, reinsert, retitghten. Repeat also on PCB under the machine. Points of failure are most likely solder or screw connectors.

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Hi everyone,

I re-soldered everything again and decided to replace the pt100 sensor with one I had bought right at the beginning of all these problems. Everything is perfect now. The ambient temperature reading is correct and I have been printing happily ever since. I'm just glad I didn't give up and buy a new heated bed (as was the advice from igo3d!).

Thanks for all the advice and help.

Regards,

Max

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Depends on what country you are in. Start at 3dsolex.com and they will tell you which reseller based on your country. Then you can get a "temp sensor" if yours is bad or a "35W heater" if it's your heater that's bad. Why do you think you need a new sensor @zxen?

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I don't know. I cannot use my printer due to an ER02 error. It was intermittent but now it happens every print. I have resoldered the black part under the heater bed 5 times. I have tightened the screws and checked the plug to the board. I have disassembled the ultimaker many times trying to solve this. Ultimaker don't come to pay my wages while the company waits for these problems to be solved, so I would now rather just pay for whatever I need to make this faulty product work immediately.

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Based on the number of complaints about the heater bed sensor, it would not be too hard for Ultimaker to send replacements for the faulty components to all their customers without delay. If they were in Australia, they would be legally obliged to a complete product recall. Just send out the parts we need to fix this faulty product, Ultimaker ;)

It could save the company.

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Oi!

Can you please not presume we all know how to achieve this? The results on this thread are visible to the world's entire internet population. I'm glad you know how to hack the firmware but can you please explain how its done? I have helped thousands of people on forums and if I know something that may be of some use, I don't hide the methodology from them. Please share if you know the steps to switch from TEMP3 to TEMP2 sensors.

Thank you on behalf of the hundreds of future readers who will have no idea about how to achieve what you have just said.

 

On the pins.h search on the board 72? I think it's 72 from memory...

Then change the pin numbers of one sensor to the other.

Edit:

Yes it's 72

 

#define TEMP_BED_PIN 10 // Bed#define TEMP_0_PIN 8 // Extruder 0#define TEMP_1_PIN 9 // Extruder 1

 

 

Change Bed pin 10 to 9 and  Temp_1_PIN 9 to 10

This should change the temperature sensor from the bed to the extruder 1 free sensor.

 

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If you ask with that much care and love ofc.

Google

Edit. Upss sorry

Google.com hit enter

Search bar, click. Type "build custom marlin ultimaker"

Edit. Upsss

Ok first chill out. Second for real I did learn how to do it by using google, this forum posts and two days searching for all the info. That was one year ago, it just takes time to learn. There's no magic recipes

Edited by Guest

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What? I learned nothing. This thread is now polluted with useless re-asking of the STEPS required to repair all the faulty Ultimakers in the world. Do you tell people who are frantic to 'chill out' and 'google it'? That's just cruel. You already know the answer. Your google search resulted in a sea of research. Please just tell us how to edit the firmware file, what it is called etc. in steps. That means, instructions. You don't have to of course, but I'm telling you there is no way I wouldn't do it for everyone. I'd be apologetic for not explaining clearly the first time.

If you ask with that much care and love ofc.

Google

Edit. Upss sorry

Google.com hit enter

Search bar, click. Type "build custom marlin ultimaker"

Edit. Upsss

Ok first chill out. Second for real I did learn how to do it by using google, this forum posts and two days searching for all the info. That was one year ago, it just takes time to learn. There's no magic recipes

 

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