Creality VR10 runaway heated bed

I have an old CR10 (not V2) and its just exhibited heated bed thermal runaway.

The thermistor is displaying the temperature accurately and when I turn on the CR10, the bed immediately starts to heat.

There is a smaller control board which I believe provides 12V to the bed based on a signal from the motherboard via a cable.

This cable is always reading ~9v.

Could this be a motherboard or specific component on the board thats failed?

Anything I can test?

Hi, I have never owned a CR10 myself but from past conversations with other CR10 owners this fault is generally either loose connections on the mainboard that might need tightening down, faulty thermistor (unlikely as yours is giving a temperature reading), or the heater block. Sometimes the heater block cables come loose and on some occasions the screw that holds the heater block in place can work loose. I would recommend checking over the printhead and mainboard and double check for any possible loose connections or loose screws.

Good luck and hope you get it up and running soon!

Thanks Nikoli,

When you say “heater block” are you suggesting the hot end? Would that have an effect on the heated bed?

Yep check all cabling to the bed and hotend as I have heard some owners have reported issues with the bed heating and it was caused by the heater block having a loose connection and as a result was somehow causing weird interference with their bed sensors.

Also double check the cabling on the bed to make sure nothing is loose cable wise. A loose connection somewhere could be causing voltage fluctuations on other parts of the printer electronics.

Also don’t forget to run a PID tune on the bed to make sure its properly calibrated.