str-de545 av amp front panel control problem

[lanarkshireparanormal]

hi all!

i have an av amp str-545 that i love to bits but it has had a problem lately, the buttons on the front panel seem to be out of sync! for example, if i press 'bass boost' it will operate 'mute' instead, and if i press 'dimmer' it will operate 'input mode' instead....it will work finaly after repeatedly pressing the buttons. anyone had this before and if so what was the repair?

thanks for your time