Case usb connector causes M/B not to power on

**nasa** · 12-16-2006, 09:51 AM

Hi,

Figured you hardware experts would be the correct people to help me with this issue.

I have this case:

http://www.opussolutions.com/index.php?p=product&id=27

and this M/B

http://store.mp3car.com/ProductDetai...Code=MTB%2D014

both bought from mp3car.com.

The problem:
when I connect the usb header from the case to the M/B the sytem doesn't power on... Even my usb mouse (connected via ps/2) doesn't light up.

Troubleshooting:
1. When system (based on the above equipment) failed to power on, I removed the header and all went well.
2. I plugged in a usb header into the M/B listd above (one connected to a slot rail) and all went well.
3. I plugged the case header into a different M/B and all went wel.

Anyone have any idea what would cause this? The troubleshooting steps would make it seem that both the header and the M/B work, but combined they don't. I checked the BIOS to ensure nothing was trying to boot of the USB ports. I verifed this by connecting a USB thumbdrive into one of the M/B USB ports and it was ignored, as expected.

Nasa

**nasa** · 12-16-2006, 10:33 AM

Back again,

failed to note that this is powered via an ATX power supply, so I doubt that power is the issue.

Nasa

**evandude** · 12-16-2006, 11:31 AM

The case connectors may have the ground wire connected to the chassis. If you hooked it up wrong, it would mean some other wire would get shorted to the chassis, so I would make sure it's plugged in the right way if I were you. Also, the case connectors could just be screwed up and have a short or something. Spend a few minutes with a multimeter and check for short circuits between all the pins on the header connector, and between all those pins and the case. Since the thing is nothing more than some wires going to a couple connectors, there's not really much else that COULD go wrong.

**nasa** · 12-16-2006, 12:25 PM

Thanks for the reply evandude,

I looked closer at both the cable/pinouts on both the usb connectors -- they are different. The one that works looks like this:

x x x x o
x x x x x

R W G B
R W G B

The questionable one:

x x x x o
x x x x x

R W G B B
B G W R B

x = female sot
o = no slot
R = red
W = white
G = green
B = Black

Motherboad pinout specs (from M/B manual for new motherboard)
USB5-6
Pin Signal Pin Signal
1 USBVCC 2 USBVCC
3 USBD_T5- 4 USBD_T6-
5 USBD_T5+ 6 USBD_T6+
7 GND 8 GND
9 Key 10 GND

Motherboad pinout specs for test M/B

Pin Signal Pin Signal
1 VCC 2 VCC
3 Data- 4 Data-
5 Data+ 6 Data+
7 GND 8 GND
9 10 OC

So since both M/B's are looking for the same thing.... Why does it work on one, but not the other. and is the one that is in question wired wrong?

Nasa