My build plate won't heat up. Any Ideas?

[Cmwade74 0]

I usually get an Error message that I can refer to, but none this time.  When I try to start a print it won't heat up.  I've checked all connections from plate to board.  Any suggestions would be greatly appreciated.

 

[Cmwade74 0]

Ultimaker 2+

[geert_2 557]

A couple of years ago this has been discussed here, with good explanations and photos. If I remember well, the most common was that the connections at the back of the bed broke, and how you could repair them, but I am not sure. Maybe you can find these posts again?

 

[MarkusBaumann 6]

If it doesn't heat up and there is no error message, the reason could be that the mainboard is getting a wrong information about the temperature of the heatbed. If the temperature sensor, a PT100, has a higher resistance because of cracks inside of the sensors ceramic body or a loosened  solder joint caused by temperature cycles and thermal stress it just gives a higher temperature value than it is in reality. At room temperature about 20°C the resistance should be around 108 ohms. If it is higher, the mainboard thinks the heatbed is already hot. I have this problem with my UM 2+ Connect right now. The resistance is around 124 ohms at room temperature which refers to a temperature of about 60°C, so when it should heat up to 60°C it just would start printing directly without heating and without error.

 

You can measure the resistance of the sensor with the sensor plug on the mainboard plugged out. If it is plugged in, you probably will get a wrong measure because of the electronics behind. You can measure at the plug and check for the cables when you move or bend them. You can measure directly at the heatbed connector and get a resistance value without the influence of the cables.