Appears the Fusion needs to be sent to Emotiva for service.
If the plan is to connect the A500 to the Fusion, that doesn't make much sense to me. Even if the Fusion is working properly, if there is a difference, it would likely be marginal, and there's a good chance for no difference. Also, that may or may not resolve the noise issue. That type of noise may not be in the power section of the Fusion, but elsewhere.