Originally Posted by dieselbobcat
The Concertone in our previous Roo23SS acted similar. It was DOA with the red light on... Solution was to remove the 12V power supply from the head unit and let is discharge any voltage. From what was explained to me, low voltage or the temporary flicker of voltage from the converter when plugging in can cause these units to hang up. I had to "reset" ours a handful of times over the four seasons we owned it.
As a easier fix, I added a momentary (NC) switch to the cabinet panel near the unit... of course since there was a easy method to reset - it never hung up again.
IIRC there are two snap on plastic endcaps, there are four square drive screws below that hold the unit. It is smaller than you would think once you remove it.
Hope this might solve your issue.
This resolved my issue. I had disconnected shore power, and then the 12V battery. After hooking everything back up, just the power light on the ZX400 Concertone. All I had to do was remove a panel from behind the unit, disconnect the 12 V connector (2 pin black and red wires), reconnect, and presto!!!