hi claudiu, there must be an editable filter on the VA76 that will allow you to turn off transmission and reception of sysex..for all your sounds to revert back to piano (which is the MIDI default by the way all channels to piano 1 and drums on channel 10) the keyboard is certainly inserting this sysex message somewhere...if i get time i will d/l the va76 manual and have a look....i know its very VERY frustrating when stuff like this happens but it is fixable
dennis