Yamaha EX5 boot up issue

Yamaha EX5 boot up issue. Half of keyboard has good sound. Flashing light display. Keyboard sometimes causes the cursor to move and page through the menu. Very perplexed over this. It wants to go to test mode. Any suggestions?

Has case been opened before? I wonder if some wiring or cable has become snagged in the mechanics of the keys. I once saw that internally on a keyboard. Rerouting the snagged cable fixed it. Also it’s why some designs use insulated metal strain relief tabs to hold long wire runs in safe positions so they don’t shift or flop around.