USB not working, Finding of problems in sequence

[Arun.shspl]

If USB Not working then how to find the problem:

1. Physically check the Usb Female Socket as its have four wire contacts in side must be good and healthy.
2. Check the +5 volts supply If not present then change the Switching Mosfet, also check the drive signal at gate.
3. Check the impedance signal lines in respect ground, it must be high restive 3k and above is good enough.if this resistance is low then need to replace south bridge, Pch now in 6th gen board only single chip that is south bridge+north bridge+cpu all in one chip (standard is IO chip).
4. If USB middle wire have high resistance or say Ok then please check USB clock, and usb PLL Supply (Phase lock loop)
5.In some laptop Like Toshiba this problem seen solved by flashing the bios.

[javed]

nice sir

[mohamedsaid]

good troubleshooting technic

[gaurav]

Thanks to share.

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[servis jaya]

Very usefull..

[bghcore]

sir i have samsung np-n100sp the flash drive, mouse and external keyboard did not recognize on bios utility and windows but 5v is present the data - & + pin 2&3 goes to tiger point ic, that ic getting heat...what solution for this problem sir

[PINTUSINGH]

GOOD INFORMATION SIRG

[anandvsalunke]

sir i have samsung np-n100sp the flash drive, mouse and external keyboard did not recognize on bios utility and windows but 5v is present the data - & + pin 2&3 goes to tiger point ic, that ic getting heat...what solution for this problem sir

Check USB load switch IC which gets short-circuited and shorts USB_OC# line to +5V, which goes straight to chipset, causing chipset heating. The USB load switch IC (usually 8 pin SOIC) also gets heated a lot. You can try to remove this ic, put a jumper to across switch and then check USB is Ok. All the best.

[samanthban]

Thanks for sharing

[elnovato]

ohhh,thanks sir,