Hello,
While working on my android tablet HU for car I accidentally desoldered smd component that is in series with D+ line for usb, there is also the same one for D-, but there is nothing writen on it. I checked with microscope...
I measured the same smd from D- and it`s not a diode, it`s resistance is 0.2ohm.
It`s black and I think it`s a 0402 size...
So ok I tought it`s a black smd, its got to be a resistor, so I soldered 0.2ohm 0805 smd resistor instead of it... But I get error message "Device descriptor request failed" in windows...
I can confirm that I get 5v on VBUS and GND if I short ID pin to GND (OTG mode), I have 96,5kOhm resistance towards the GND from both D+ and D- lines...
That would confirm that everything is soldered correctly, no shorts...
That being said, that SMD component must be something else...
I can find no schematics only of any phone, tablet...
Does anyone know what would it be?
It`s a black SMD, I think 0402 with resistance of 0.2ohm in series with D+, where is another one in series with D-, followed by common choke...
Thank you for your time and help
While working on my android tablet HU for car I accidentally desoldered smd component that is in series with D+ line for usb, there is also the same one for D-, but there is nothing writen on it. I checked with microscope...
I measured the same smd from D- and it`s not a diode, it`s resistance is 0.2ohm.
It`s black and I think it`s a 0402 size...
So ok I tought it`s a black smd, its got to be a resistor, so I soldered 0.2ohm 0805 smd resistor instead of it... But I get error message "Device descriptor request failed" in windows...
I can confirm that I get 5v on VBUS and GND if I short ID pin to GND (OTG mode), I have 96,5kOhm resistance towards the GND from both D+ and D- lines...
That would confirm that everything is soldered correctly, no shorts...
That being said, that SMD component must be something else...
I can find no schematics only of any phone, tablet...
Does anyone know what would it be?
It`s a black SMD, I think 0402 with resistance of 0.2ohm in series with D+, where is another one in series with D-, followed by common choke...
Thank you for your time and help
You are right, that is the lead resistance, my bad... I don`t know how I forgot to measure it.
I tryed to bypass the resistor and it does not work, that`s telling me it is not a fuse or zero ohm link...
Well I hope someone will know whats going on... I cant find any schematics of usb simmilar to my circuit online, it`s frustrating...
It could be. It`s used for minimizing EMI right? But usb didn`t work bypassing it. Do you think it shouldn`t?
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.