Me again with another usb problem. This time we have a sony laptop which has a MBX 250 motherboard. This board has 1 usb only but has another 3 usbs with ribbon cable card. 5V is ok. But rest of 3 pins are grounded. Data - and data + pins are grounded. I desoldered the usb but still same. When i measured the other 3 usb ports i get the grnd , 3.3v and 5v, all ok. Windows or dos doesnt find usb ports. I found schematic. But i couldnt find where usb data pins are connected. These are some detailed photos and schematic.



I checked these 3 ports. Ground is ok. 5V ok. Data pins are showing 3.3v.



I checked these 3 ports. Ground is ok. 5V ok. Data pins are showing 3.3v.

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