you should now reheat the solder.
I recommend you take the bed apart again and heat up the two connectors to the sensor with a soldering iron (and add a tiny bit of solder to assure that you heated it hot enough). Melt the solder and then continue to heat it an extra 5 to 10 seconds to be sure it's very hot.
Do you have images?
I did not understand where i need to reheat.
Several people had a cold solder joint there which can have invisible cracks where electricity can't flow. This would cause intermittent problems and it can also cause bad temp readings without causing the firmware to declare a total failure.
But this could happen at a random time even if previously was working?
But this could happen at a random time even if previously was working?
Yes it could. Definitely. I hope you have a soldering iron or know someone who has one.
I thought I posted pictures above - let me check.
i have and can use the soldering iron.. just need to understand if the solder to renew is the one of the plate connector (and if yes wich one)or the one of the board under the u2.
No picture above... :mrgreen:
This is the problem when you post the same issue in 3 different topics. My posting with the 2 photos is in response to your posting over in this other topic:
http://umforum.ultimaker.com/index.php?/topic/4227-is-leaving-the-ultimaker2-alone-safe/?p=35118
If you follow the link in my post, or in the next post that you made there is a photo of where the screws are circled in red. The messy looking area where the screws are - that is where the 4 solder spots are. Reheat the 2 with the thin wires until the solder melts and reflows. You should add a tiny bit more solder also to prove that it is melted and that there is plenty of solder there.
so i need to tighter the two centered screw here:
No - I think it's the right 2 screws. The sensor is the smaller/thinner wires.
More information and photos here:
http://umforum.ultimaker.com/index.php?/topic/3745-had-a-problem-with-my-um2-heated-bed/
i report the photo here to create a more understandable topic.
ok so the screw just hold the cables and the magic is with the solder! Why ultimaker didn't choose a screw connector to make the connection just with the screw? When yesterday i unmounted the plate i thought the contact was made by the screw and not by the solder. Now it's clear.
Ok tomorrow i will check mine.
How are they supposed to connect the screw terminal to the PCB without solder? You can't have one without the other.
i checked the cables and renewed the solder. Nothing changed.
Maybe now the sensor show a lower more stable temperature.. but always wrong.
You can see in this video that even if the plate is set at 0° it read 63°..
https://www.dropbox.com/s/cvczi8lw26qdtbi/2014-01-31%2016.25.44.mp4
The support now contacted me.. i hope they can help me.
I would cut power, remove the connector on the bottom PCB and measure the resistance...
The problem is I don't know what thermistor is in the Ultimaker 2. Someone posted it somewhere but now I can't find it (just searched). ANYONE OUT THERE KNOW WHAT THERMISTOR IS IN UM2 HEATED BED????
Simmon - I think you should ask this question of support: support.ultimaker.com
Found it:
PT100
is there a way the bed is broken? I think it has a really simple science behind that can't be broken..or am i wrong?
What i do not understand is why suddenly doesn't works.. in the first prints was ok and hot..
Here's a table that links temperature in C to Ohms:
http://www.intech.co.nz/products/temperature/typert/-200to239c.gif
So 63C means the Ultimaker thinks it is 124.4 Ohms. But if it is cooler - say around 21C then it should be 108.2 Ohms.
Here's what you should do:
1) Turn off UM2
2) Flip on it's side, remove the bottom cover. It's only 1 screw I think. I've only done this 3 or 4 times so far. It's very easy. Remove the LARGER bottom cover only.
3) Remove the "temp3" cable - it's on the top of this image towards the right next to the 2 ribbon cables.
4) Measure the resistance of the cable - it should be about 108 ohms if things are working but I expect you will read closer to 124 ohms.
If you get 108 ohms - put it back together and if it still reads the wrong voltage you need a new PCB - contact support.ultimaker.com
If you read more like 124 ohms then take the bed apart again and measure at the bed. Measure at the actual temp sensor. Maybe you have to resolder the temp sensor pins? Maybe you need to replace this PT100 RTD part. They cost less than a stick of gum.
the ultimaker 2 has a this PT100 RTD ? i need to check the bottom.. is the only think i don't have seen yet.
While i'm waiting the replacing bed...
Is there a way i can print without heated bed? I mean with blue tape? or something like that since i have not one..
Put a 100 or so ohm resistor in there to fool the printer.
Then, yes, you can print on cold glass or on blue tape. If cold glass you will need to add some gluestick:
http://umforum.ultimaker.com/index.php?/topic/3404-printing-on-glass/
If you print on the blue tape, make sure you re-level after the tape is on and also clean the blue tape with isopropyl alcohol to remove the wax:
Hi!!!
today the new heated bed is arrived!!!!
Now my little ultimaker can start again to works!!!
I need to publicly thank Marrit Hoffmans for her support and all the mail she answered.
Now it's time to print!
P.S. gr5 you are my technical reference point of the forum!! Thank you too!
'I recommend you take the bed apart again and heat up the two connectors to the sensor with a soldering iron (and add a tiny bit of solder to assure that you heated it hot enough). Melt the solder and then continue to heat it an extra 5 to 10 seconds to be sure it's very hot.'
gr5
i have the same problem for my UM2
it works for me after i re-solder all 4 connectors at the back of the heated bed
Here is how I needed to fix the heater bed sensor (ER02):
The little screws that hold the temperature sensor to the heater bed are pointy.
As the build plate moves around, they loosen. So you tighten them.
Unfortunately, they carve out the plastic like a drilling machine.
So replace them with screws that are the same size but with flat heads like little bolts.
These are holding well for me.
The sensor needs to be pulled tight against the heater bed, otherwise the Ultimaker will shut down to prevent burning your house down for safety.
1
VERY IMPORTANT NEWS:
I just discovered you can still print when the heater bed sensor is broken by starting your print, then adjusting the heater bed temperature on the Ultimaker to ZERO. The error doesn't show at all.
(You might have already known that.)
Resoldering the PT100 joints did the trick for me. Do not attempt with cheap tools or without some SMD rework experience.
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gr5 2,172
It would be good if you didn't post this same problem in 3 topics. Anyway, the problem can be in several places:
1) at the PCB underneath
2) In the wiring
3) At the bed
The problem is with the temp sensor wires. By far the most likely is #1. I know you tightened the screws but you should now reheat the solder. Several people had a cold solder joint there which can have invisible cracks where electricity can't flow. This would cause intermittent problems and it can also cause bad temp readings without causing the firmware to declare a total failure.
#3 is second most likely but the connector would have to be barely connected and rather obvious.
I recommend you take the bed apart again and heat up the two connectors to the sensor with a soldering iron (and add a tiny bit of solder to assure that you heated it hot enough). Melt the solder and then continue to heat it an extra 5 to 10 seconds to be sure it's very hot.
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