Thanks for the info! That´s quite frustrating, along with the complex mixer! I´ve purchased this keyboard because i´ve experienced some problems with my lovely WK-3500! Apparently the problem is in the main board! So i had wanted to buy the WK-3800, which is quite similar to the WK-3500, but i didn´t find this model here in Portugal! Due to scheduled gigs with the band that i play, i´ve been «forced» to buy the WK-7600! It have great sounds, interesting features, but doesn´t have the «Tone with wave» (sampler) function that i use to play Mellotron sounds and it´s very much difficult to use than the Wk-3500!