He's complaining about your cross-posting the question to multiple threads.

Anyway, back on topic...

All of the ground loop problems you describe sound like they're caused by a wiring fault somewhere. I don't know if the fault is internal to the player, internal to the tuner, or external to both, but everything you've been saying, all the way back to the problem with the whine-in-tuner-mode-only, sounds like some kind of a fault where there's an intermittent connection or a shorted wire someplace.