Marantz MA-500 cutting out...

[bendiesel]

So...I have an amp that is cutting out at moderate to high volume. It cuts out, then clicks like its restarting then cuts out again.

Another observation I have is that when the defective amp is powered up it takes much less time to get that initial relay(?) to click.

Any help or suggestions provided are greatly appreciated.

Thanks!
Ben

 

[east electronics]

replace all electrolytic capacitors .... dont think that if you replace the big ones you are going to solve the problem

the small ones a responsible for the the correct operation of amplifier while the big ones is only a reservoir of power used to supply the amp with power

 

[Tekko]

It might also be the overcurrent protection kicking in due to too low load impedance, or overheating.

 

[east electronics]

not really ...read Tekko :when the defective amp is powered up it takes much less time to get that initial relay(?) to click.

 

[sgrossklass]

I would say it's a combination of two independent issues. The turn-on delay may be defined by an RC time constant, and the C is a small electrolytic that's dead, as sakis suggested. Cutting out at high volume usually points to an emitter resistor that's gone high in value. Solder joints are always worth a look, too.

Determining the state of the big buffer electrolytics is non-trivial, typically requiring an ESR meter or measurement of supply ripple under load.