Hey guys, I just put together a home built system to replace my old desktop. Everything went pretty well until I tried to use a self-powered USB hub. After I plugged it in the USB port, it worked well, but after I turned the PC off, it won't power up unless I unplug the USB hub. Any ideas why this is happening? The USB hub I'm using looks like this:
I had the identical problem with a hub which looks precisely the same as the one in your pic. Problem was maddening.
PC would power on and work fine, but when I connected the USB hub, would not switch on - no fans, no lights, nothing.
Drove me mad - in the lab PC would power on fine, but at my desk, nothing.
Took a completely different PC - same symptom.
Finally I narrowed it down to the USB hub - power from the hub must be feeding back to the PC. Removed the hub and PC works properly. I'm not sure if it's the hub or its dinky switched power supply.
Same symptom on a Gigabyte medium quality motherboard and a different system with a medium quality ASUS motherboard.
I just realized the same thing with a new system. I have a ASUS X79 Sabertooth MB and it has diagnostic LEDs on the MB and I noticed the stand by LED was still on with the PSU plug disconnected. I then unplugged the USB cables and it went out immediately. When the computer won't power up I just unplug the hub and it fires up immediately. I am using some cheap hubs off Ebay so perhaps I will buy some better powered hubs now.