means: the safety overload protection breaker is clicking on inside making that “clint" sound
reasons:
1) one of your capacitors on one of the channels inside the unit is blown
2) you have impedance on speakers that is larger than the unit can drive check Max ohms is not greater that the units Output…..this can also happen in reverse, ie: you are using speakers too low to be connected to the unit, as soon as you up the volume you will hear the capacitor shut off and make a “Clint” sound inside the unit, this is the protection breaker and will display overload on the LED panel.
3) you have Wires out of phase (meaning positive is in a negative somewhere on the speaker or rear of the unit)
Checkpoints:
1) Disconnect each speaker and turn on until the problem ceases, this will determine which speaker is had it, or out of phase.
2) if you are powering speakers A and B External at the same time, turn one off, as the speakers do not match to be run at the same time with A and B running
3) lower volume as well as turn between left and right balance to check those capacitors aren’t fried inside the unit
4) if you disconnect all speakers and inputs and turning on the unit still activates the protection breaker and Overload is still showing…..means your Amp is had it, and one of the main pots (that look like Dcell Batteries on the main circuit board ) are toast. if your competent in checking under the cover, you will see that the top silver area on top of the capacitors are starting to bulge, they should be flat on top, if they appear to be splitting open, means they need replacing. only a qualified service technician can replace and repair those.