CF-31 usb back port not working

Hello everyone, I am recently experiencing issues with some CF-31 usually MK5 (CF-311xxxxx) one of the USB port at the back does not work, now it's been like 5 or 6 units with the same issue and it is always the one beside the dual pass connector, all the rest work normally. I tried replacing either the ribbon cable, the usb board from same model and nothing worked out. Bios has USB enabled. Does anybody have a clue what could I try before replacing the whole motherboard? I appreciate any help.

 

I have doubts that it is a motherboard issue. I bet all the rear ports use the same controller on the motherboard. Why would just one port fail? Seems odd to me.
Is this port USB 2 or is it USB 3?
What OS is this?
Maybe try a USB stick with Linux on it. See what the ports do with Linux.

 

Yes, for me it's hard to believe that will be a MB issue, however if I plug 4 USB sticks in the ports and boot to BIOS, I can see only 3 of them under EXIT tab. It should read them all (I can see the 4 USB on BIOS in a working unit). They are 2.0 and I'm trying with 2.0 stick. So basically I am testing USB's before any OS version.

 

I know that the BIOS won't see / boot a USB stick in a USB 3 port unless you set the USB to "legacy" port.
Doesn't help you much though.

Did the problem ports ever work? I have seen custom BIOS's that have various hardware disabled.

What are you normally plugging in to that port? Just had a thought that maybe your USB devices are blowing the fuse on that USB port. Panasonic should have a separate fuse on the motherboard for each port. The fuses are VERY small.

 

hmm, they are set to legacy, and I just plugged regular USB stick 2.0. I am going to check if there's something I can do with the fuse.

 

Here is a photo of the fuses used on the motherboard.
This is not a CF 31, but it gives you an idea of what to look for.

 

I appreciate it!

 

Sorry my computer had a fit and I had to reboot.

 

Here