I am trying to repair a pair of Mackie CR3 active speakers which seem to mute shortly after powering up.

The circuit is based around a TDA7265 amplifier IC (see attached). I have been trying to trace the mute circuitry from the IC but noticed D1 and Z2 have different symbols with the same part number (IN4148)? One is a standard diode symbol and the other a zener diode symbol.

I asked Mackie (LOUD Technologies) about this anomaly but they said they can only give out information about schematics to authorised service centres!

 

Does anyone have the full schematic for the CR3? There is a fault in the -12V line on mine, and am trying to debug it - a circuit diagram would be a great help. Thanks.

 

Here we go

 

Pin 5 is the Mute function, make it Positive to supply for Sound, and Ground for Mute..

 

Here we go

Is there a complete schematic?