I have hunted around and tried everything I can find to try. I am out of ideas now. I built a reprap from scratch. Using a Mega and RAMPS 1.4 with Marlin. When I first built it the heated bed worked fine for the first couple prints (I did get some errors on repetier temp reset error id BED - it was something like that). Then quit working completely. I assumed a bad RAMPS board. I replaced it same thing. Replaced the bed heater, same thing. Here is what I see.
Using Repetier, I click on the heat bed icon. It says "Heating bed". The RAMPS board does not light up, I checked the voltage on the power block for the bed. There is 0 volts. Disconnect the bed wires and I get the same thing.. EXCEPT 1X yesterday. The RED LED lit up and there was 12v on the power block. I disconnected in Repetier, Unplugged the USB cable and powered down the power supply. Reconnected the bed wires and powered everything back up.. STILL no bed heat, no volts and no LED. Disconnected everything again and once again have 0 volts and no LED. I tried a brand new RAMPS board out of the package with a new arduino MEGA with the same results. I have tested the power coming from my power supply and its showing 12v going into both 12v rails on the RAMPS board.
There are NO errors whatsoever in Repetier. It seems to think it is trying to heat the bed.
If anyone has any ideas on what to try next let me know. I have still another MEGA and another new RAMPS board (it's a maker space). I will try that if someone thinks that the other 2 I tried are faulty.
