After first doing a Google/YouTube search, There was only one "hit" on my search results. Next I went to an appliance message board forum but after almost a week and more than a dozen views, no response was received. This is unusual. I've been on this board before with positive results. They also changed the "rules" for DIYers which could explain why I didn't have a lot of response from the experts.
I attempted to get the unit into diagnostics mode. I was unable to clear the E90 "general communication" error code and so I'm also unable to access diagnostic mode. I decided to order the main control board from AppliancePartsPros.com a site I've used before. Their quality parts, competitive prices & fast shipping will keep me coming back.
After installing the main control board, I wanted to try getting into diagnostics mode to see if anything else might be "faulty". Again I was unable to enter diagnostics mode. But the E90 error code was certainly gone now. Needless to say I was anxious to run a load of clothes through the washer. Voila! It works. It was a very easy fix. Even after I dropped a couple of screws & buttons & springs which I found a put back into place.
Of course after I put in the new control board, I received a reply from the appliance message board forum. Most of the proposed solution was what I already Googled. There was a tip about re-seating all the electrical connectors and spraying with a QD Electronic Contact cleaner. I will try this in the future if it happens again. I did thank the person for their reply & tips.