Lenovo cm3a760me motherboard USB port cannot be used for repair

Motherboard model: Lenovo cm3a760me motherboard

Fault phenomenon: USB port of motherboard cannot be used

Maintenance process:

Motherboard boot into the system are normal, that is, P port and USB port can not be used, keyboard and mouse can not be used!

Lenovo cm3a760me motherboard USB port can not be used repair Figure 1.
Plug in the USB port mouse, the lights are not on, there must be no VCC.

Lenovo cm3a760me motherboard USB port can not be used repair Figure 2.
According to the drawing, USB VCC is supplied by p7533am8 small 8 pin chip, and there are several such chips in the whole board.pin,VCC.Both 1 and 2 pin have 5V, and 4 pin has 0.25V. The problem must be in the en signal.The en signals of all chips are connected together.Run schematic as follows.

Lenovo cm3a760me motherboard USB port can not be used repair Figure 3.
USB_EN is sent out by IO chip 84 pin, measuring en to ground Diode value is normal and forcing to USB_En a 5V VCC, all p7533am8 have 5V output, should be pull up broken.In a simple way, add a 4.7K resistor to a chip on the side.Paint scraping,add solder, install a resistor, power on,Normally booting up.The copying machine is in good condition. The troubleshooting is over.