I have everything else working and my bed won’t heat I tested the bed and it works off the 12 v supply With the wire to the heat bed unplugged the terminals on the board read 10 v when i put the wires in those terminals read 0 and thus not sending power to the bed The light for the heated bed works as dose the therest it cuts the light off when the bed comes up to heat Really need help I’ve looked everywhere for a solution
Sounds a bit like a broken FET. There are two black MOSFET’s on your board for dealing with the high current demands of the heatbed and the hotend. First establish which one is for the heatbed, secondly use a voltmeter to measure the middle pin on the MOSFET, this pin is called the gate and it is the control signal for ‘activating’ the MOSFET. When the bed is on this pin should be high (5V) and when the bed is off this pin should be low (0V). If this isn’t the case then it’s not a broken MOSFET but rather a broken board.
ruggb
3
for info ; IF the INPUT is 12V and the hotbed is OFF and the terminal reads 10V there is a FET issue = it is leaking (or your voltmeter has an EXTREMELY high input impedance). IF the hotbed is ON then the FET has a problem as the on resistance should be under 1 ohm. A 2V drop would indicate a very high on resistance. That would yield 0V with the hotbed connected.
