the question was not directed at me, but I had some Sun-2000G-WAL die several times, just fix one a month ago , they usually pretty easy to fix… not sure if your have the 4 led on them to tell when it working as mine does - red, green,green, green ( the speed of the cycle through the greens, indicates how much output) or the one with the LCD . but if it has the LED here a basic diagnostics .
if there no wind and and there no red light the issue on the AC side. if there wind and it on then it usually on the DC side.
it usually the little fuse that popped on the AC side but once it was the triac .
if it red with the ac and wind. then it can be several things . usually it the rectifying bridge has shorted. ( the big diode that the 3 phases connects too.) test and replace if shorted … if it red and the dump load is hot then the relay has welded closed . and you have to replace that ( you also hear is clicking on and off when you plug and unplug the AC power) . the last is the ICs. if you have a ohm meter with diode function that beeps just test the legs on each ICs against the the other leg on that IC (the one mounted to the box for cooling ) if they beep then one or more have shorted you need the replace that bank of with the same ICs . the last issue I had, was the large capacitors. if they are are leaking then you have to replace them. they are hard to find that are exactly the same physical size. but the smaller ones worked fine - hope that helps you a little bit and you get it working again