I’ve got an ANET A8. Recently, as many of us A8 owners will, I discovered the connector to the heated bed was turning black. So I while I was fixing that I decided to add a MOSFET to control the bed. But the bed isn’t heating, and it seems the MOSFET isn’t switching on. The light on the mosfet is on, it’s getting 12v according to my multimeter, but the outputs are at 0v all the time. The motherboard connection from the heated bed to the MOSFET ‘control in’ is fluctuating between 10.5v and 11.98v, sort of randomly. The power supply is capable of a total of 600W. Is the MOSFET DOA, or is there another problem I should look at?
You have a multimeter, so I’m assuming you made sure you have positive and negative coming off the board to the right place on the MOSFET?
I did. The board in question is this one. The diagrams I consulted to hook this up say that the “Control In” JST connector at the top comes from the board, and that polarity of this connection isn’t an issue. Not an expert, though.
Just tried testing the mosfet’s on and off modes, and I think the mosfet is DOA. If I’m doing it right…
Yeah that’s the one I have on my A8 and a2. If you have positive and negative in from the power supply corrdct, and made sure the positive and negative for the bed from the board, you should be fine. Polarity going to the bed doesn’t matter, the rest does as i understand it.
Try switching the control wires from the motherboard to the mosfet
