Thanks gunrunnerjohn, for your patience. And, yes I installed "LibreOffice." Let me attempt to recap.
1 - I'll remove both sound boards leaving the motherboard in place.
2 - There are 4 wires from the locomotive to the tender that go into the motherboard (J2) purple, black, red, and white.
Question 1 - do these four (4) wires stay in the motherboard or do they go to the ERR? I think they stay in.
Question 2 - And/or leave the four (4) wires (J2 - purple, black, red, and white) in the motherboard, and connect from the motherboard using a four pin plug to the ERR?
If done based on question 2, the ERR board should have power, serial data, and speaker supply.
3 - After connecting from the motherboard to the ERR Board - connect with a 2 position wire to the right of the speaker connector, and then take the multi position plug (with purple, and black on it), and connect to the 9 position male on the ERR board (top right).
Does that sound right?