My studio 540 died. Over the last year, the rear USB ports were dying one by one and I had to move everything to the front (I know this by troubleshooting). Then it wouldn't restart unless it cooled down so we just left it on. One day it just died. The power supply LED is green in the back, but the front indicator went amber once and now nada. No fans, no nothing.
I swapped out the PSU and did the green to black wire test and the fan on the new PSU worked but still nothing. I swapped out the mother board and CMOS and still nothing. Everything inside is disconnected, ram is out, cards are out, still nothing. I jumped the front switch, nothing. Other than the 24 pin connector and the PSU power cable to the board and the chip fan to the board and the front switch cable, nothing else is connected to the mother board. Nothing, I disconnected the fans and still nothing.
So new board and PSU and nada. Any ideas?