If I can stop in here for a moment as a non owner. (not yet) Hope what you are seeing is a loose wiring harness or connection. The amount of reostats and pots on the new ones still eludes me. Something I'll have to look closer at. Hope these are easy fixes and both of you report back.
"What is a weed? A plant whose virtues have not yet been discovered."
Ralph Waldo Emerson (1803-1882)