How to Troubleshoot & Replace Samsung AP4455125 / DC92-00130A Assy Pcb Sub;Purple W

Disassembled the unit, top and display assembly, and found a shorted/burnt connector wire leading from/to the smaller display assembly PCB. The forums lead me to either the larger display assembly PCB or the main power board. After rewiring the burnt pin in the connector, I replaced the display assy PCB and that did not cure the problem. I then ordered both the smaller display PCB and the main power board. One piece of info that may be of value to others is that the pins to the burnt connector were all powered independent of the power switch, which is not correct and should have led me directly to the main power board. Upon replacement of the main power board, the unit works great. Now I need to return the two display assembly PCBs, since neither was the culprit. 

I replaced the board that has the power button on it since the power button wasn't working properly for some time. I also got help from an online forum where a lady with the same appliance and the same problem first replaced the main power board and only fixed the problem after replacing the sub-board. She also included a link to this website for the part for a great price.