I have a Toshiba SA-775 that has never let me down since new. However, the "click" that I used to hear when I flipped on the switch doesn't occur anymore and as a result I get no sound. Took it to a well know service shop but even though they believe it's likely a amp/preamp relay that would protect the speakers when the unit is first turned on, they don't have a service manual, etc. for this old unit in order to properly check it out. Can anyone help me? Thanks.