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Bed Thermal Runaway - this time slightly different  

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stefan.a3
(@stefan-a3)
New Member
Bed Thermal Runaway - this time slightly different

Hello,

(Prusa i3 MK2S with MMU, current firmware and Windows software)

I'm getting the above message and searched the forum. Unfortunately, in all cases I found, it was a '100% broken' topic. Either a wire was broken or the thermistor was faulty.

To me, this happens differently:
I'm printing a flat rounded object which should last about 3,5 hours.

After 4 layers and about 75 minutes, the bed is getting colder .. slightly... it takes about 20 minutes to cool down from requested 85° down to 82° then minutes later it stops with the BERD THERMAL RUNAWAY message.

Any idea how to solve it? The self-test is OK, but it doesn't take that long.

Unfortunately, any try takes about 90 minutes to see a result 🙁

 

This topic was modified 1 year ago by stefan.a3
...
Posted : 03/07/2020 9:18 am
karl-herbert
(@karl-herbert)
Illustrious Member
RE: Bed Thermal Runaway - this time slightly different
Posted by: @stefan-a3

Hello,

(Prusa i3 MK2S with MMU, current firmware and Windows software)

I'm getting the above message and searched the forum. Unfortunately, in all cases I found, it was a '100% broken' topic. Either a wire was broken or the thermistor was faulty.

To me, this happens differently:
I'm printing a flat rounded object which should last about 3,5 hours.

After 4 layers and about 75 minutes, the bed is getting colder .. slightly... it takes about 20 minutes to cool down from requested 85° down to 82° then minutes later it stops with the BERD THERMAL RUNAWAY message.

Any idea how to solve it? The self-test is OK, but it doesn't take that long.

Unfortunately, any try takes about 90 minutes to see a result 🙁

 

I think the thermistor cable has a loose contact between the heating bed and the printer board. After a certain amount of time, the wires are brittle due to the many movements. Measure the resistance of the thermistor (should have 100kohms at 25 degrees C.) and see what happens when you move the heating bed.

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 03/07/2020 4:36 pm
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