Hi, I am working on a Hp 15-cs2023ca Laptop, Logic Board # DAG7BMB58C0 REV: C. The motherboard works fine but the USB 2.0 does not work at all & gives Error "unknown usb device (device descriptor request failed)" in Windows 10. I checked the 5v & GND, both fine. Checked the coil of TX & RX, resistence between both the point is around 400Khms & no shorts at all. Does this signal come directly from the SOC??? If someone can put in their expertises on this issue, I would appreciate. Thanks in advance.
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Hp 15-cs2023ca USB 2.0 not working
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Re: Hp 15-cs2023ca USB 2.0 not working
Remove all power. Meter in diode mode.
Red meter probe to ground.
Black meter probe to the D+ on the usb connector. What is the measurement?
Repeat with D- on the usb connector (black lead on meter). What is the measurement?
You may have local esd diodes that are damaged. Other faults may be an onboard usb hub controller that links to these ports. Check for the IC nearby.
Check the diode values against a known good USB port on any laptop.
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Re: Hp 15-cs2023ca USB 2.0 not working
Originally posted by mferna14 View PostThanks for the reply. This has Only 2 USB ports & built-in USB 3.0 in it. I am only concerned about the Generic USB 2.0 which should work & now not working for some reason. More info pls. ask me. Thanks
According to available G7BD schematics (not sure how close it resembles DAG7BMB58C0) the only elements between the ports and the PCH would be the ESDs or USB multiplexer. If you say your USB3 works fine then the multiplexer is out of the way iMHO.
See if USB power stays at steady 5V when you plug devices in.
Go for data lines with oscilloscope and see if they are sound/stable.
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Re: Hp 15-cs2023ca USB 2.0 not working
Originally posted by mon2 View PostRemove all power. Meter in diode mode.
Red meter probe to ground.
Black meter probe to the D+ on the usb connector. What is the measurement?
Repeat with D- on the usb connector (black lead on meter). What is the measurement?
You may have local esd diodes that are damaged. Other faults may be an onboard usb hub controller that links to these ports. Check for the IC nearby.
Check the diode values against a known good USB port on any laptop.
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Re: Hp 15-cs2023ca USB 2.0 not working
Actually that is a good thought to follow.
To rule out software issue try booting off a Linux usb and see if they work there.
I've seen win boxes having usb description read issue while trying to read usb2 devices in usb3 port.Last edited by cruiser_; 09-21-2022, 02:36 AM.
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Re: Hp 15-cs2023ca USB 2.0 not working
Originally posted by mferna14 View PostI mentioned the meter reading for the Data lines, both are almost 400Khms, & the 5v is always present, the voltage is not fluctuating at all, stable as ever. I checked, but there does not seem to be any protection diode. After the coil, the circuit is directly going to the SOC, I am assuming this as I do not have the schematics for this model. I have a used another SSD with fresh Windows 10 on it & still gives "unknown usb device (device descriptor request failed)"
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