Water in base of unit. I checked the Drain vent and drain to disposal & it was fine. Called service person to evaluate/repair. He noted that the check valve/flapper was misbehaving. However, to replace the flapper, he'll have to order the new assembly motor included. Labor & parts will be $299.00 plus the the $79.99 service evaluation. He recommended a new unit.
After he left, I noted the M/N and check with ApplianceParts Pro. The service person was credible in noting the assembly. I watched APP's Tutorial Video to insure I can execute as illustrated.
I ordered the unit and installed it following App's Tutorial. After all said & done. Results - Successful. My wife stared at me as if I was Einstein