UM2 Heated bed burnt out terminal block

[Verne64 0]

I have this ultimaker 2 (added olson block and using Ultiarjan's extruder), which failed to heat it's bed without giving an error. I dissasembled the bed, to find nothing wrong. So I dug on, exposing the motherboard, to find the PCB terminal block connecting to the power wires was completely burnt out (see pic).

Image

I suspect a faulty connection was the culprit but I am really not sure. I now have to repair the printer and have two questions to which I cannot find a clear answer (had a phonecall with ultimaker support but they were not sure either).

How can I know if the heated bed itself is still usable? I have three of them lying around, one which definitely works and two that are suspected to be defective. I measured the resistance over both the heating element and the sensor (removed beds from printer/power supply & made sure they were room temp). All three of them return identical values, about 3 Ohm on the heating element and around 110 Ohm on the sensor. Are there any other measurements I can perform to tell me anything about the status of the bed?

How can I find out if the motherboard is lost? I have some spare PCB terminals of this size lying around, maybe I could just replace the terminal on the board and see if it still works?

If anyone has any tips on finding out if my components are still usable, they would be greatly appreciated!