Hi ! I own a K4 keyboard, too. But the 'main board' where is located
the 'processor', RAM memories, main supply...crashed down. I replace
a 'main supply' IC. 9 volts appears now, but the 'display' only shows
some '%&$)((=?' characters, not sound, not MIDI signals, nothing. If
someone can supply me this circuitboard, eMail me to:
oficinacbuin@..., please. I am Eduardo Ibarra, Limache, V
Regiòn, CHILE, Southamerica...Thanks in advance.