After Firmware Update (3.0.11) and auto PID Cylce: Bed Temperature dropping after short time into a print
 
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After Firmware Update (3.0.11) and auto PID Cylce: Bed Temperature dropping after short time into a print  

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alexander.s27
(@alexander-s27)
Estimable Member
Re: After Firmware Update (3.0.11) and auto PID Cylce: Bed Temperature dropping after short time into a print


i sat and watch it happen once the red led light on the bed stopped flashing and then the bed temp dropped 15C and thermal runway occurred.

I would bet my a** that this is no thermal runaway but a broken cable, possibly very near the heat-bed connection where there is most of the movment. Although the isolation looks ok the strands in it are broken and are in contact not all the time.
Had that myself two times, already.

Heat your bed manually with the settings menue and move your bed back and forth, play with the cable, wiggle and jiggle it.
You eventually will see the light flashing.
Soldering it again is no big deal...

Posted : 20/12/2017 3:16 pm
JuanCholo
(@juancholo)
Honorable Member
Re: After Firmware Update (3.0.11) and auto PID Cylce: Bed Temperature dropping after short time into a print

well i tried what you suggested and the light stayed solid.
if it is a broken wire it is completely intermittent.
i spent 10 minutes on preheat moving the bed front and back and it stayed at the set temperature.

all this started with the newest firmware upgrade. no problems then the hour i installed the newest firmware on the very first print the machine shutdown about 1 hour into the print with the bed thermal runaway error. since then it has had the issue.

“One does not simply use a picture as signature on Prusa forums”

Posted : 22/12/2017 2:30 pm
alexander.s27
(@alexander-s27)
Estimable Member
Re: After Firmware Update (3.0.11) and auto PID Cylce: Bed Temperature dropping after short time into a print


well i tried what you suggested and the light stayed solid.
if it is a broken wire it is completely intermittent.
i spent 10 minutes on preheat moving the bed front and back and it stayed at the set temperature.

all this started with the newest firmware upgrade. no problems then the hour i installed the newest firmware on the very first print the machine shutdown about 1 hour into the print with the bed thermal runaway error. since then it has had the issue.

No, you did not exactly what I did suggest.

Do NOT concentrate on the temperature!
Although it could be a temperature misreading this most probably is a broken power-cable for the heatbed, not the sensor-cables.
Temperature change of the bed is way to slow to find the broken part by watching the temperature.
Heat the bed manually with the settings menu at a fairly high temp, so that the indicator LED at the bed "stays on".
Moving the bed may not be enough, move the cables, you may even have to pull somewhat, flex and bent them.
Eventually the LED will go out! That is where the strand is broken.

I am pretty sure, that it is not about a misreading due to the new firmware.
But anyhow, if it is something with the cables, as I am sure it is, this will get worse with the time and easier to locate....

Posted : 22/12/2017 3:40 pm
kafi
 kafi
(@kafi)
Active Member
Re: After Firmware Update (3.0.11) and auto PID Cylce: Bed Temperature dropping after short time into a print

I have the same problem after upgrade to the latest firmware. My MK2 runs over 18 months without problems. The last year i print only PLA, now i will upgrade my MK2 to MK2S (with upgrade kit) and would print the upgrade tiles. Now my MK2 runs to the "Bed Thermal Runaway" error 😥

Posted : 03/01/2018 9:21 pm
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