A lot of very good points made by many here. Very good posts.
As some mentioned, exactly how long does it take to diagnose where exactly the problem is? That actually takes more time than pretty much anything else. The OP mentioned two chipsets. Well, how long did it take to find that the problem was the two chipsets?
Typically, unless the amp displays error codes like modern cars, the tech has to start in certain sequence and move forward.
For example, disconnect everything from the power supplies and see if the power supplies are actually working.
If so, connect one side of the amp to the power supply, see if it works, then disconnect that side and connect the other. Slowly bring up the voltage.
These are just small examples.
Diagnose the protection circuitry, etc. yep, I hate to tell you but, these take some time. Unless I knew exactly what the problem originally was, I would take my time and go in sequence.
So, the time spent, actually does make sense to me.
I work on electronics all the time and I also restore classic cars and I work on cars also.
I own and restored a 1983 Volvo 244 Turbo. It had a low oil pressure reading on the gauge and the idiot light. Know what the problem was? wasn't the gauge or wiring, wasn't the oil pump, bearings, etc. it was a stupid five cents o ring on the oil pickup tube. yep. had to drop the oil pan (stupidly difficult on this car), had to move the steering rack and lots of other things to get that oil pan off, remove the oil pump tube.
This took an entire weekend.
So, having worked on (and still to) and repair and upgrade audio equipment, I can tell you that although it took them some time, I can see why it might have.
enjoy
As some mentioned, exactly how long does it take to diagnose where exactly the problem is? That actually takes more time than pretty much anything else. The OP mentioned two chipsets. Well, how long did it take to find that the problem was the two chipsets?
Typically, unless the amp displays error codes like modern cars, the tech has to start in certain sequence and move forward.
For example, disconnect everything from the power supplies and see if the power supplies are actually working.
If so, connect one side of the amp to the power supply, see if it works, then disconnect that side and connect the other. Slowly bring up the voltage.
These are just small examples.
Diagnose the protection circuitry, etc. yep, I hate to tell you but, these take some time. Unless I knew exactly what the problem originally was, I would take my time and go in sequence.
So, the time spent, actually does make sense to me.
I work on electronics all the time and I also restore classic cars and I work on cars also.
I own and restored a 1983 Volvo 244 Turbo. It had a low oil pressure reading on the gauge and the idiot light. Know what the problem was? wasn't the gauge or wiring, wasn't the oil pump, bearings, etc. it was a stupid five cents o ring on the oil pickup tube. yep. had to drop the oil pan (stupidly difficult on this car), had to move the steering rack and lots of other things to get that oil pan off, remove the oil pump tube.
This took an entire weekend.
So, having worked on (and still to) and repair and upgrade audio equipment, I can tell you that although it took them some time, I can see why it might have.
enjoy