What is the normal volume of your convection oven? Ours sounds like it's preparing for flight and doesn't cook very evenly in conv mode. Is this normal for a combo oven? I'm wondering if there might be a fan issue.
Don't know about the noise, but are you using the wire rack/stand to put what ever your baking on in the oven on conv mode? The DW found that that's a must for even baking.
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2012 Winnebago "Journey To Insanity" 40U
2008 Dakota Sport 4x4
2004 Subaru Baja - DW's
2006 Honda Shadow Aero - TOAD for now. F.R.O.G. member