Hi again,
I connected my heater bed this week. I bought the ramp here on vicious, all other things i bought somewhere else.
The problem:
I start heating the heatbed and the extruder. It says heating extruder and stops around 125 degrees.
Then i get error: heating failed, system stopped - heater id: bed Error printer halted
I got the extruder on 10 and the heaterbed on d8. Thermistor on T0 (extruder) and T1.
Where does this error come from?
I just bought the other stuff here too now, tired of things not working the way they should. Hope that i can see the difference. If someone still has the answer: I would love to hear it and learn from it.
Do you have a fan cooling the ramps ? Both the mosfet and the fuse for the bed can get pretty hot. I thought I was clever and replaced the mosfets with better ones so i wouldn’t need cooling, but the heatbed polyfuse got too hot and switched off with a similar heating failed error 
(PS… the real reason I switched the mosfet’s was because I melted one cause I forgot to connect the fan while I was messing with it :D)
There isn’t any heat at all. If i remove the heatbed everything is working fine again. But the heatbed doesn’t get warm, same as the ramps.
Sounds like its not getting power at all.
You did connect power to both inputs on the ramps board right ?
Jupe, both on d8. Repetier does find the heater, since it is not removed out of the list (what happened before)
Tried switching the cables but that made no difference. Maybe we did something wrong with the cables. But if I turn on the heatbed there is no voltage on the screws either (voltage on extruder is fine). But the error comes in later.
Could be that the mosfet is broken but don’t know why it would. Haven’t done anything weird.
Are you using at least a 20A power supply?
Eh, not sure if we misunderstand each other, I meant the green input plug on the ramps, needs all 4 wires connected. Just trying to check the most obvious thing ?
Didn’t use at least 20A, but I do now. Made no difference, still got the error. I will re-order the ramp and get the heatbed from you. Hope that will work. Think my misfet is broken (have tested it) Yea I have all 4 wires connected.