Heatbed won't stop heating

[Gerry]

Hello,

As stated in the title - the printer's heatbed (Acrylic Prusa I3 with Sanguinololu) won't stop heating. Furthermore, it starts heating right after I power it on as opposed to the extruder which maintains a (somewhat) constant ambient temperature. The top temperature of the heatbed is around 130 C even when the specified top temperature is set to 70 or 95 C. Tried reinstalling the firmware, resetting the printer, plugging/unplugging - nothing helps. What should I do next?

Kind regards,
Gerry

[zhangxueyou]

Please check the resistance of hot bed.

[Gerry]

Checked resistance. Close to zero, looks like it shorted. Already ordered new heat bed. Any advice on keeping the next one working properly without shorting it?

[zhangxueyou]

Check the resistance before using, the resistance should be more than 1.2 ohm. Test the resistance at the 2 ends of hot bed wires.