Unrecognized USB device problem - Page 1
Forum section: electronics / repair

author: Jawad
author_rank: Contributor
timestamp: July 17, 2019, 12:05:53 pm
content: I have a problem with some USB devices that turn always to be unrecognized (some of them don't even get detected on windows when plugged) this is an original diagnostic interface made in Sweden, two of them cause the unrecognized message on Windows and one don't even get detected.the 3 interfaces are a bit expensive (those are my brothers interfaces each one cost 2k) that's why I want to repair even just one of them, since they power up when plugged to a vehicle, and I already opened them none of the components seem to be burned or somethingWhen I plug it to a computer the detection sound plays and the unrecognized message appear and all the lights on the interface blink once.it's like they tried to be powered one but there is short so it shut down itself (i'm just a beginner in electronics so don't jugde my conclusion)What I think is something is blown causing the connection between the USB port of the device and the computer to stop. but didn't find any source on how to diagnose this problem and don't know where to start to solve this problemWhat could possibly be the cause so I will narrow my researchtake a look at the attached pictures to see the 3 different boards, although the design is different they are the samethe Bottom side goes to a connector which goes to the USB port of the computer

author: coromonadalix
author_rank: Super Contributor
timestamp: July 17, 2019, 02:25:05 pm
content: Unrecognised could mean there is no drivers found in or for windows via its web searchYou can search its vid and pids in the device management in windowsCreate a desktop icon with : devmgmt.mscYour yellowed / error item / properties / details / select hardware propertes id's / copy ex: VID_0403&PID_6001 and do a web searchOr ask the maker for the drivers ?? and or any schematicAnd try to find the usb interface ic, check every usb protection mechanism, tvs / tds diodes, resistors, inductors, broken pcb pads

author: Jawad
author_rank: Contributor
timestamp: July 17, 2019, 05:00:49 pm
content: Thanks for the answer coromonadalix but it is not a driver problem i'm a computer engineer already checked that first + if I plug another working interface (same one like the damaged ones) it works fine but the other ones don't so it is not a driver problem and it is not a port problem already checked it too.the problem is in the interface but don't how to debug that to find what's wrong

author: magic
author_rank: Super Contributor
timestamp: July 17, 2019, 09:14:17 pm
content: Something being blown by transients is a possibility in automotive stuff, but a common failure in all computer electronics is power supplies.Start with version 3 because it's a simple, uncluttered board. I hope you can recognize electrolytic capacitorsAlso the yellow bricks with orange ends are tantalum capacitors, so they are capacitors too.Connect the board to power, get a DMM and check voltage on all capacitors (carefully, don't short something out with the probe). It all should be reasonable numbers like 12V, 5V, 3.3V, 2.5V, 1.8V, 1.2V. If there is something else, it may be a problem.Technically, there are some ceramic capacitors as well, but ignore that stuff. Pretty surely every one of them is in parallel with some bigger cap.

author: coromonadalix
author_rank: Super Contributor
timestamp: July 17, 2019, 09:56:32 pm
content: In version 3 you have a cypress chip, try to find its datasheet ?The parts to be checked in red circles (joint photo) normally on the 3 blue inductors, you should have on one side an dc voltageYou have a 5 pins regulator, try to find its datasheet too, it may be a switching / dc-dc regulator ?

author: Jawad
author_rank: Contributor
timestamp: July 18, 2019, 08:05:14 am
content: Thank you guys for the replyI will test what you suggested.For the top capacitors they are for the power coming from the vehicle.and they are working fine since when i connect it to the vehicle it stays powered on (led on) the problem only on the usb side it powers on and shuts off( the led should stay on)I will test those capacitors and report backThank you

author: wraper
author_rank: Unknown
timestamp: July 18, 2019, 10:10:15 am
content: Quote from: coromonadalix on July 17, 2019, 02:25:05 pmNo it does not. It's certainly a sign that windows failed to communicate with the device. Certain malfunction, either in device, cable or PC. All it takes to see such message is pulling UP one of data lines with a resistor. So device may be completely dead and not even try to communicate.