Repair tips for 500W Audio Amp

[gjh]

Any tips for repairing the following Audio Amp - https://www.megamusiconline.com.au/product/behringer-eurolive-vq1500d-15-inch-powered-pa-subwoofer-500-watt/

It seems to be melting the ground wire between the onboard AC socket and PCB before blowing the fuse.     Dont really see anything obvious inside besides a bulging electrolytic cap.   I guess one of the amp/power transitors  could be gone drawing more current.    It's been awhile since I did circuit theory in school.     Apart of purchasing a thermo camera (something Im thinking about for home leak detection)  whats the best way to troubleshoot ?

[Messtechniker]

1.) Measure each capacitor in-circuit.
2.) Extract those which do not measure OK in-circuit.
3.) The replace those which do not measure OK out of circuit.

[gjh]

1.) Measure each capacitor in-circuit.
2.) Extract those which do not measure OK in-circuit.
3.) The replace those which do not measure OK out of circuit.

Will give that a go.    I have a ESR Meter as well    

[mengfei]

Isolate & Test

Isolate the Power supply section from the AMP & the test the supply alone then you can go from there
for power amps usually it's the output or power supply problem. Sometimes some relays gets stuck too
take it out of the metal casing & just check the PCBA making sure that there is adequate GND

[Messtechniker]

When testing power supplies on their own,
dont forget that some will need a load.

[knudsenuk]

Agree, isolate the psu first, emulate the psu with a bench psu (with current limiting) connected to the amplifier module and also measure the DC offset on the output which I suspect will be skewed heavily in favor of one supply rail, giving you an indication of the likely failure, also one rail will be drawing much more current from the supply. Obviously if it is a genuine 500w then it it may be hard to the operating voltage from a bench psu.