basic electronics question

The 1 blown N channel MOSFET was the issue the whole time. Guy offered it to me for $40 telling me it buzzed then kept blowing the 2.5A fuse. I did a little research on it over lunch before buying it and found the majority of solid state amp issues of this type are blown output transistors (MOSFETS) and I had replaced a bunch of them in a flat screen power supply and a 2500W inverter. I knew they were only a few bucks a piece so I took a chance. I was a little gun shy of powering the thing up without finding the root cause as these MOSFETs were special order and didnt want to pop it again without running the schematic past you guys who know better than me. I was waiting for a "check diode D23, they ALWAYS crap out in that circuit" or something like that. I usually suspect capacitors in anything electronic as those are the first to go, (checked all of them out of circuit, no faults) but this one displayed a short (blowing fuses) and bad caps usually don't do that, they just don't power up or power at a fraction of the voltage they are designed for. They are usually easy to spot as they are bulged on top, like they overpressured and blew up the perforated metal 'lid', or if the circuit does manage to power up, you can sometimes detect a bad one with a laser thermometer as a hotter one. Even if they appear to be good, its pretty easy to unsolder a leg and put an ESR tester or better, a cheap ebay component tester on it and it will display the actual capacitance and ESR.