Remove all power sources from the inverter. Turn off the AC, and DC to the Inverter. Wait 15 minutes for the capacitors to discharge any residual DC energy. Then proceed after determining all electrical power both AC and DC have been safely disconnected. Follow all company related safety protocols to avoid accidental electric shock. Failure to comply may result in injury or death.
Remove exterior screws for the top cabinet, You will need a long thin Torx Bit T-20, T-25 to reach most of these. Amazon Link
Open cover from LEFT side (while facing the front), do not remove it completely. Hold it slightly ajar, it’s easier with another person. Extract board from inside the inverter. Cover should still be attached, nothing should be disconnected other than the board.
Use a pair of pliers to compress the plastic locking bracket located in the center of the board. While compressing the locking bracket, gently wiggle the board with your free hand to remove it from the inverter.
Put cover back on, ensure no wires are pinched at the bottom of the cover, tighten all screws and test communications.