Oppo 105D high frequencey sizzling issue anyone help me suggesting a mod that i can do or?

Ya No .. so I have had the Oppo 105D since April 2014 and have enjoyed it and never had an issue .. until lately ..

I am getting a high frequency sizzling at the tweeters via the dedicated balanced 2 channel outs.

With less of a revealing interconnect one can not hear it at my listening distance of 10 ft but I do want to keep my WireWorlds Gold Eclipse 7s .. as they are so open and revealing ..

I know that its the Oppo as I have isolated and changed out speakers, cables, interconnects, power cords and by passed my power conditioner as well and all leads point to the noisy audio board.

So I contacted Oppo and it would be $119 for them to put in a new board .. very reasonable I think .. however they cant guarantee me that it will solve my issue as they cant duplicate my exact set up and interconnects..

with the above stated .. maybe I should look into a modification as we all know there is a lot of mods that can be and are done with the oppo 105.

Maybe I try things myself? Thinking of trying to emi rfi shielding the power transformer, power supply cover, transport lid 
 Any suggestions and real world experience that you may have are greatly appreciated.

Thank you for your time .