The monitor's control buttons have stopped working. When receiving a signal the monitors image displays perfectly, albeit unadjustable. When no signal is present the monitor enters its' R/G/B/B/W test pattern sequence; again lacking any button control. I've replaced the menu function board (P/N 5E31Q03001); however, that did solve the problem. I'm looking for advise for a next step or a source who could extend that help.