![[H]ard|Forum](/styles/hardforum/xenforo/logo_dark.png){kind=logo}
I built a computer for someone in a Thermaltake Xaser III case, model V1000A. The motherboard of choice was the MSI K7N2 Delta-L. This board does not have any Firewire headers, but it does have an extra USB header and the obligatory front-panel audio header.
Before powering the system on, I made sure I had everything plugged into the motherboard: all ribbon cables, front panel items, "front" USB and audio (they're on the top of the case), fan RPM sensors, etc. I ran Memtest86 v3.0 for about 4 days and there wasn't a single error. I loaded the OS and drivers, applied updates, and ran SiSoft Sandra burn-in loops for another day, which was fine. However, when I plugged anything into the USB ports on top of the case, nothing happened. The ports on the back worked, but not the ones on top.
I examined my connections, and they were all correct. I hadn't plugged the top USB wires in backwards; +5V, D-, D+, Ground. I noticed something strange, though. Normally, this is what a USB header would look like:
This, however, is what the Thermaltake case's USB header looked like:
Instead of the 5th pin being blank, there was a ground wire looping into it, complete with another pin that connected to the motherboard. Now, the motherboard header has 9 pins: 5 on the top row and 4 on the bottom, with the one in the lower-right corner being a key. Just out of curiosity, I unplugged the top USB ports' connectors and removed the looped-around ground wire from the connector, and then plugged the ports back into the mobo. The ports then proceeded to work flawlessly.
The only thing that I can think was wrong, was the fact that there were two ground wires. Is there such a thing as "double-grounding"? If so, is it bad, and why? I'm just curious ... I've never had this kind of thing happen to me before ...
Before powering the system on, I made sure I had everything plugged into the motherboard: all ribbon cables, front panel items, "front" USB and audio (they're on the top of the case), fan RPM sensors, etc. I ran Memtest86 v3.0 for about 4 days and there wasn't a single error. I loaded the OS and drivers, applied updates, and ran SiSoft Sandra burn-in loops for another day, which was fine. However, when I plugged anything into the USB ports on top of the case, nothing happened. The ports on the back worked, but not the ones on top.
I examined my connections, and they were all correct. I hadn't plugged the top USB wires in backwards; +5V, D-, D+, Ground. I noticed something strange, though. Normally, this is what a USB header would look like:
This, however, is what the Thermaltake case's USB header looked like:
Instead of the 5th pin being blank, there was a ground wire looping into it, complete with another pin that connected to the motherboard. Now, the motherboard header has 9 pins: 5 on the top row and 4 on the bottom, with the one in the lower-right corner being a key. Just out of curiosity, I unplugged the top USB ports' connectors and removed the looped-around ground wire from the connector, and then plugged the ports back into the mobo. The ports then proceeded to work flawlessly.
The only thing that I can think was wrong, was the fact that there were two ground wires. Is there such a thing as "double-grounding"? If so, is it bad, and why? I'm just curious ... I've never had this kind of thing happen to me before ...
