the radio is look is working
why speaker dont make any sound on 2001 Mercedes-Benz S600
Could be the radio is bad, or if it has an amplifier it can be bad too, of there can be a wiring issue. It will need to be diagnosed to know for sure.
Mine did the same thing. It did it a couple times then it would eventually come back on. Check that out. I was told that the amp goes bad when that happens. I never check it out. Then I had a problem with something killing the battery with the engine even off. After a month of research they found out it was the radio. The motherboard in the radio was destroyed. It took two batteries and a month of analysing to found out.
what did you do to the motherboard? did you have it replaced? mine is doing the same thing right now.