First try plugging it in directly to the USB port on the computer to see if tis the miner or the hub. Maybe the hub burned out or is causing to low of electric to the miner. If you test it/them on the computer directly and there is no problem, either replace the hub or Just unplug it and plug it back in until it begins working. Maybe you had the FREQ settings to high and they got so hot they melted or burned something inside the hub. Mine do that all the time and just by unplugging them and plugging them back in they initiate 
He already test that. It's clearly stated on the OP.
