freetown fred wrote:OP stated none of this is the problem!
You don't know what *isn't* the problem until you find out what *is* the problem, LOL.
The OP's assertion is that since he can plug into the controller and no work vs wall and it does work, it must be the controller.
Maybe. But if the controller is trying to run fans at lower speed, it could still be the controller, OR it could be the fans getting marginal due to maintenance or partial failure.
In which case, it is possible for the FANS to burn out the CONTROLLER, which would likely happen again...or could also continue to fail until finally dead.
I've seen these kinds of electrical failures in other types of systems, Fred. They are quite common.