Bed temperature is changing randomly

While printing the bed temperature is changing like this -3212/55 . If the print time is below 30 minutes, printers stops after print two layers. But longer then 30 minutes, finishing job. I changed bed thermistor but problem still going. There was no problem until upload the Marlin Bugfix 2.0 . I connected BL TOUCH on my printer and its working correctly. I didn't change any PID or temperature settings on Marlin Bugfix 2.0 2-hour print has just been successfully completed. But when i print something for 10 minutes the printer stops working

Printer : My own design COREXY
Firmware : Marlin Bugfix 2.0
Motherboard : MKS Base V1.6
Slicer : Prusa Slicer

Could you post a Image of the LCD controller cables all the way to the controller.
If the can not be inclusive to a single photo diagram route to the controller include distances.

Edited 1 time(s). Last edit at 01/02/2021 08:23PM by Roberts_Clif.

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Computer Programmer / Electronics Technician

LCD cable is 60 cm.

It could be a defective LCD display, though in my opinion this is not to likely.

When my 3D Printers started experiencing garbage display an some strange infrequent axis movements, I went thru great lengths to discover the problem.
Finally discovered the EMI "Electromagnetic interference" was the cause, solving the problem was quite easy..

Moved the LCD far away from the Controller as possible. This reduced the problem with my controller on front frame.
Solving the Problem was done with using Aluminum Foil Duct tape.





I covered the complete inside of my controller case opening the air vents and grounding the Aluminum Foil Duct tape.
Still experiencing an infrequent EMI problems covering the Ribbon cable with Aluminum Foil Duct tape completely solved the problem.

My suggestion is the line your controller box with Aluminum Foil Duct tape including the inside of the cable Duct run to the LCD,
The Aluminum Foil Duct tape should cover the cable Duct snap groves this will insure that the snap on top is also grounded.

This may include placing a small grounded piece of Aluminum Foil Duct tape between the Stepper motor and LCD ribbon cable.

Anyway this was the solution that solved my problems, hope the information help you.

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Computer Programmer / Electronics Technician

Thanks for your attention and advice. I will try and share information about the result.

I tried it and problem still going. I removed lcd and printed with usb cable. The result is same. I printed something for 8 hours yesterday which is compeleted successfully. But for 10 mins print, its stopping working. Its make me crazy

Have you checked the stepper to see if it is overheating. or do you have a fan cooling the controller.

Is the Z-Axis height in the same neighborhood.

Post your Marlin configuration.h and Configuration_adv.h also post the original config files if you have them.

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Computer Programmer / Electronics Technician

İts always stopping on 3. layer
Yes, i have fan cooling.
Here is the files.

Edited 2 time(s). Last edit at 01/04/2021 03:55PM by DEMİR.

sorry but There is no Marlin 2.0.8 download your version of marlin from here

It would be anyone guess to what has been changed in the firmware.
Then using Notepad++ or Winmerge to compare the two files making it easier to duplicate the configuration to a known stable version of marlin...

Edited 1 time(s). Last edit at 01/04/2021 08:52PM by Roberts_Clif.

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Computer Programmer / Electronics Technician

I had similar symptoms; putting a fan on my ramps and stepper drivers assembly fixed motors giving out during prints. I have also had Garbled display and skipping/shifting layers. Maybe I had interference as well, but haven't had an issue since removing my lcd board. I'll keep the interference in mind when I get to putting it back on.

i uploaded marlin old version which is i was using before upload Marlin Bugfix 2.0 and i configured bltouch settings. Now, there is no problem about thermistor, lcd or anything. It seems problem is in Marlin Bugfix 2.0 and Marlin 2.0.7.2