Heatbed suddenly heating and it wont stop

Hello i am new user this forum and i have a problem with my 3d Printer. As soon as i open the 3d printer, the heatbed starts to warm up also it doesnt stop. I do not do anything about the temperature.Heatbed warm up to 90°.what has it got a problem my 3d Printer please help me. Does this create problems from 3d Printer now thank for your comment

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malio77
Hello i am new user this forum and i have a problem with my 3d Printer. As soon as i open the 3d printer, the heatbed starts to warm up also it doesnt stop. I do not do anything about the temperature.Heatbed warm up to 90°.what has it got a problem my 3d Printer please help me. Does this create problems from 3d Printer now thank for your comment

I assume the printer is disconnected from PC when this happens? (no software running it) I would suggest to check your wiring. If everything OK then check the MOSFET driving the bed. Maybe it died and remain shorted which would explain why it heats up immediately when powered up. Also, have you been modifying the firmware? maybe something not setup properly? You need to do some troubleshooting.

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Printers: Heavily redesigned TwoUp with E3D V6 and Robo3D R1+ with Chimera/Cyclops

If no software changes have been made, then I would suspect that you have a shorted Mosfet driver circuit.
To test with power off remove the bed wiring to the controller and measure the resistance across the bed terminals of the controller this should be infinite (OPEN).

malio77, it is considered spamming to cross post in different sections of the forums. Please don't do that.

I have merged all the replies here and deleted your extra copies of that topic.

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Most of my technical comments should be correct, but is THIS one ?
Anyway, as a rule of thumb, always double check what people write.