First let me start by saying my knowledge of electronics/elecal is very limited and everything I have has come from this current issue.
I will receive my fourth ramps 1.4 board today and want to make this one work without a hitch so I don't have to return it. My set up is a onyx heated bed. My meter has a resistance of 1 ohm and my bed reads 1.8 ohms. So I'm getting a reading of about .8 for the bed which is low. I have a 12v 30 amp PSU. It puts out 12v directly however when I measure voltage out of the do terminal I am getting 9.5-9.8v. No looking at the specs of the mosfet I am limited to 95 watts. Now if my math is right I an currently delivering ~113 watts which would explain the over heating issue. If I increase my ohms to 1.8 I will be at 80 watts which should be fine. My question is if I put a resistor in my positive heated bed line (I have 2 18 gauge wires) could I increase the resistance and solve the issue.
Note I never had an issue with my mk2 heat bed and for the first 2 weeks had no issue with the onyx bed
Note 2 I have no shorts anywhere all my wires are nice neat and separated.
Note 3 Only the heated bed terminal is causing issues and it's been the same with 3 boards.
If anything is wrong with my assumption please let me know. Also if there are any suggestions or if the resitor idea will work what do I need.
