Heating bed over heats

[jhoarty]

Hello, I have the exact same problem! My Prusa i3 is the Arduino Mega 2650 board with Ramps 1.4. I have been successfully printing now for about a month and the heatbed suddenly won't stop heating up!

[zhangxueyou]

Hello, I have the exact same problem! My Prusa i3 is the Arduino Mega 2650 board with Ramps 1.4. I have been successfully printing now for about a month and the heatbed suddenly won't stop heating up!

Cooling MOSFET is very important, how do you mount the mainboard to acrylic board?

[jhoarty]

Ahhh yes, the fan wires are very weak and one broke. I will need to buy a Ramps and a new fan from you. I will do that now. Thank you!