I wanted to let others know I was able to solve an issue with my PX-860. The piano developed a buzzing tone coming from the right side when I played B and B flat, mostly B though. It was not digital, but rather a resonant frequency of something in the speaker or cabinet... Anyway, I read through a bunch of threads and noticed others having the same issue or similar. Long story short I knew it was mechanical, not software related and I began removing parts starting at the top. It didn't take long to find that the open/close lid mechanism was the source as the issue was gone once the lid was removed. Specifically, there is a sheet metal tab that traps the slider bar/wire part for raising and lowering the lid. The metal tab has 2 screws, one at each end. This piece, I believe, was buzzing. In order to access it you first need to remove the screws from each of the hinges in the back first. I added some elmers glue to the threads of each screw when I re-assembled and now the piano is buzz free.
