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PSA for MSI board owners w/front panel USB troubles

Posted: 2006-12-08 02:03pm
by Glocksman
I recently built a new system using an MSI 945P-Neo3F board.
Whenever I'd plug something into my front panel USB ports, the computer would hard lock.

Before RMA'ing it back to newegg as defective, I decided to check out the MSI support forums for advice and it's a good thing I did.

Linky to problem and the fix
The trick is to make sure that pin 10 (at least on a K7n2 delta-L), the pin labeled USBOC (USB Open Connection), is wired to NOTHING. If the connector to your front usb ports is fused into one giant connector and it HAS a wire that will connect to this pin (labeled GND2 or Shield or something), CUT THAT WIRE. Pin 10 on JUSB2 (at least on a K7n2 delta-L) must be OPEN. If this pin IS connected to something (even if it is only GND), the motherboard will think something is connected to this usb port and you will get many unknown devices listed in your windows device manager and the rest of your usb ports may or may not work.
In summary: all usb ports/headers have only four pins associated with it (VCC, USB+, USB-, GND). If the connector (whether it's one big connector or individual sockets) to your front/top usb port has 5 sockets, don't connect the 5th socket to anything. That goes for any case/motherboard combination. This is what i'm talking about above. I have no idea why motherboard and case manufacturers have a 5th pin involved in any way on either the pin or socket side. It is not used for usb.
My front case connector didn't have that wire, but my floppy bay card reader did, and despite it working perfectly, the lead was making the ICH think that the USB ports were shorting out whenever I'd connect a thumb drive to the front panel ports.

After removing the #10 pin connector, all of my USB problems magically went away. :D

Posted: 2006-12-08 02:05pm
by Darth Wong
I've never heard of a 5-pin USB internal connector. There's only the 4-pin ones and then the 10-pin two-wide blocks where one pin is sealed in order to make sure you put it in the right way.

Posted: 2006-12-08 02:18pm
by Glocksman
Darth Wong wrote:I've never heard of a 5-pin USB internal connector. There's only the 4-pin ones and then the 10-pin two-wide blocks where one pin is sealed in order to make sure you put it in the right way.
It's the 10 pin connector with the sealed (#9 position) pin.
In this case, the pin (#10) opposite the sealed pin was connected to the card reader as an additional ground, and MSI uses it for USB overcurrent sensing instead of a ground.

The header from the front panel doesn't have this 9th wire, as it's an 8 lead connection with the sealed pin like you note.