Chosen Solution
Mac mini Late 2012 - 2.3 ghz Core i7 , - The USB ports (all4) stopped working - after I plugged all the usb devices: scanner printers hard disks -around 10-11 devices- and they were all turned on and connected to the computer via self powered usb hub, and when I started the computer I had a (USB device drawing too much power) error message , and all the usb went down , I researched and did all the suggested solutions I tried resetting NVRAM/ PRAM , and SMC. with no result, I ran the Apple Hardware (Extending) Test and the result was surprisingly “No trouble found” pass number 1 .. I re-ran the test again pass number 2 got the same result “No trouble found” yet still the usb problem exist. could it be a hardware malfunction, if so is it possible to replace the USB ports or hub or its controller only from the logic board instead of replacing the whole board?, n.b.: everything else is working fine (firewire, thunderbolt, ethernet, bluetooth, wi-fi, earphone … etc)
The Mac mini’s USB ports have two functions, the USB signal and power for devices like a mouse. As you state the powered Hub is not able to access the USB signal side of the connection back to the Mac Mini this implies the USB hub chip inside the Mac Mini is damaged. Using the powered hub (powered) allow us to make sure the power side of the Mac Mini’s USB ports wheren’t the issue as the power from the independent power supply would feed the devices connected to the hub (not any of the mini’s USB ports). You could also use a USB tester like this one: USB Charger Doctor Current Voltage Charging Detector Battery Voltmeter Ammeter to test the USB power service from the Mac Mini. Sadly, at this point I think your logic board is damaged.
i have the exact same problem - did your thunderbolt workaround work? if so what product did you use? Thanks
