Quote Originally Posted by AbuMaia View Post
I have the relay board (from MakerFarm) connected thus: the two wires soldered to the relay board I have plugged into D8 on RAMPS. Negative wire from the power supply plugs into IN, one wire from the heat bed plugs into OUT. The other terminal block holds the Positive wire from the power supply and the other wire from the heat bed. I did not have to make any firmware changes to use the relay board. I use motherboard 33.
Are you sure that's correct? I configured mine according to the Makerfarm site which says:
Quote Originally Posted by MakerFarm
Connect J2 to one heat bed wire and GND from your power supply. Connect J1 In to 12v+ from your power supply and connect the other heat bed wire to J1 out, then connect the two small Pre-Soldered wires to your Heat Bed out put of your electronics (D8 for RAMPS, Heat bed port for Printrboard etc)