? Buzzing sound from control panel?

Thanks to all for that feedback. I'm sure that's the problem,ie the factory installed converter.the buzz can come on shore power or off line. Since purchase of the TC 2 years ago I had a Xantrex HFS inverter charger and TM 2030 battery monitor installed by a local RV mechanic. ( But I'm not sure he knew what he was doing. "Too many wires " was all he had to say,and was obvious he had never such an upgrade before.(I lost all confidence when I had to rewire the battery disconnect I had him put in)At any rate I'm a retired ER Doc and don't trust electricity,so My question is I guess I should have it repaired/replaced.? Is it a risk? Is my Local RV mechanic or CampWorld RV service center likely to be able to replace/repair? I was kinda hoping the after market Xantrex inverter charger would have somehow bypassed the factory installed converter/charger.