Usb voltage 5v to 0v

[lgf700b]

Hello everyone. I have a LA-4854p Acer mobo with broken usb ports. This mobo have only 2 usb ports and both broken. I pulled out old ports and soldered new ones. Board worked well. I checked new soldered usb pins. No short circuits and checked 5v voltage. But there is a problem. When i plug in an usb device, 5v drops to 0v.





I checked pins of D23 , C538 , U28. They are all working properly. What should i do.

[cyberhack]

Re: Usb voltage 5v to 0v

check that you have not fitted the wrong usb ie usb1

[lgf700b]

Re: Usb voltage 5v to 0v

Checked and desoldered both sockets but nothing changed. Still 5 to 0v.

[lgf700b]

Re: Usb voltage 5v to 0v

I'm getting closer. When something plugged to usb, board cuts power. Something is making short circuit with usb but what? By the way i replaced U28 too.

[lezsimply]

Re: Usb voltage 5v to 0v

Make sure you check the proper positioning of the port you just soldered.

A few months ago I made a mistake of replacing the port. The port is almost identical until I noticed that the inside pins are inverted. Check the images I attached. hope this helps

[lgf700b]

Re: Usb voltage 5v to 0v

Make sure you check the proper positioning of the port you just soldered.

A few months ago I made a mistake of replacing the port. The port is almost identical until I noticed that the inside pins are inverted. Check the images I attached. hope this helps

You know i just figured it. My ports are reversed ones. Thank you man.

[lezsimply]

Re: Usb voltage 5v to 0v

No problem

[tomodachi]

Re: Usb voltage 5v to 0v

Happened me once before, good u noticed quickly

[cyberhack]

Re: Usb voltage 5v to 0v

did tell him to check that he has not fitted usb 1 instead of usb 2 in the 1 post oh well

[sasser]

Re: Usb voltage 5v to 0v

so it means lgf700b not fitted well usb1 and usb2? is that different

[sasser]

Re: Usb voltage 5v to 0v

im also face with this problem i replace with the new one usb port. actually both i pull out from another acer machine. till now usb cant detect but 5v is present.

[lgf700b]

Re: Usb voltage 5v to 0v

I fixed that board yesterday. I didnt have laptops bottom case so i didnt figured that ports reversed.

[sasser]

Re: Usb voltage 5v to 0v

oh im understand reversed mean u soldered in wrong position right.

[lezsimply]

Re: Usb voltage 5v to 0v

in some way yes, check post #5. same solder points but different pinouts.