Mackie 1400 Muting Circuit Problem

[mapeda]

The amplifier its working normally at any volume and the status could be Stereo, Mono or Bridge. It make mute, turn on only both protect leds and mute for a few seconds and keep working normally. But sometimes this procedure repeats many times, I mean the amplifier its working fine and mute without any reason and works fine again, but sometimes too the amplifier works fine all time.
 
Anybody knows what could be happening?

[David Houck]

If you haven't already, you may want to give Mackie technical support a call.

[xlrogue6]

If it's out of warranty, I'd call S&X Pro Audio at 206-575-1704.  These guys used to be Mackie in-house techs--Mackie is referring all non-warranty service to them.