Pioneer xdj 1000mk2 distorted sound

I've got a problem with my player, when connected to mix via link, there is a sound distortion. I've tried everything, changed cables, flash discs, tied every single channel, but the problem remains! The second player (also 1000mk2!) works perfectly good! I've got the latest firmware update 1.41. Is there a possibility that it is caused by firmware! I' ve tried to reinstall it, but it was not possible! When I plug flash disk with firmwarw, there was a message that latest version is already installed! Is it possible to reinstall it, with older version or anything else??? Thanks for advice.