# Mavlink Inspector works but no vehicle connection via USB

**URL:** <https://discuss.px4.io/t/mavlink-inspector-works-but-no-vehicle-connection-via-usb/30123>\
**Category:** Pixhawk\
**Created:** [December 17, 2022, 10:22pm UTC](https://discuss.px4.io/t/mavlink-inspector-works-but-no-vehicle-connection-via-usb/30123 "2022-12-17T22:22:32Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Axel\_Blumenthal](https://discuss.px4.io/user_avatar/discuss.px4.io/axel_blumenthal/32/11998_2.png) [@Axel\_Blumenthal](https://discuss.px4.io/u/Axel_Blumenthal)\
**Post date:** [December 17, 2022, 10:22pm UTC](https://discuss.px4.io/t/mavlink-inspector-works-but-no-vehicle-connection-via-usb/30123/1 "2022-12-17T22:22:33Z")

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Hi, for a while now i tried to set up a mavlink router system.The Holybros s500 PX4 i work with spontaniualsy stopped working.All i did was changing some parameters in the MAV Tab and QGC only shows me the incomming stream via MAV Link Inspector but not a connected Vehicle. (Windows connects sound ,disconnect sound, connect sound)

So far i tried:  
MP connection ,failed  
Another USB Cable,failed  
Another USB Port, failed  
Diffrent PC , failed  
Reinstalling QGC ,failed

An this happend twice. I stopped working with the first PX4 and used another one but after a day the same failure accured. I can buy new ones but i have the slight feeling that this happens again.

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**Author:** ![JulianOes](https://discuss.px4.io/user_avatar/discuss.px4.io/julianoes/32/30_2.png) [@JulianOes](https://discuss.px4.io/u/JulianOes)\
**Post date:** [December 19, 2022, 3:59am UTC](https://discuss.px4.io/t/mavlink-inspector-works-but-no-vehicle-connection-via-usb/30123/2 "2022-12-19T03:59:49Z")

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You say that you changed params and now it doesn’t work? In that case I would try to reset the parmams and try if that fixes it. I think there is a “reset params” button in QGC.

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**Author:** ![Axel\_Blumenthal](https://discuss.px4.io/user_avatar/discuss.px4.io/axel_blumenthal/32/11998_2.png) [@Axel\_Blumenthal](https://discuss.px4.io/u/Axel_Blumenthal)\
**Post date:** [December 20, 2022, 11:50pm UTC](https://discuss.px4.io/t/mavlink-inspector-works-but-no-vehicle-connection-via-usb/30123/3 "2022-12-20T23:50:16Z")

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Sadly there is no option for this because there is no vehicle connecting. I only changed mavlink parameters.

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**Author:** ![JulianOes](https://discuss.px4.io/user_avatar/discuss.px4.io/julianoes/32/30_2.png) [@JulianOes](https://discuss.px4.io/u/JulianOes)\
**Post date:** [December 22, 2022, 7:40pm UTC](https://discuss.px4.io/t/mavlink-inspector-works-but-no-vehicle-connection-via-usb/30123/4 "2022-12-22T19:40:59Z")

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Have you tried to connect with a daily (newer) version of QGC?

[https://docs.qgroundcontrol.com/master/en/releases/daily\_builds.html](https://docs.qgroundcontrol.com/master/en/releases/daily_builds.html)

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**Author:** ![Axel\_Blumenthal](https://discuss.px4.io/user_avatar/discuss.px4.io/axel_blumenthal/32/11998_2.png) [@Axel\_Blumenthal](https://discuss.px4.io/u/Axel_Blumenthal)\
**Post date:** [January 19, 2023, 11:10am UTC](https://discuss.px4.io/t/mavlink-inspector-works-but-no-vehicle-connection-via-usb/30123/5 "2023-01-19T11:10:54Z")

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I reinstalled a older version and it worked again. Then i uploaded the newest one and it worked also.  
Thanks for the support.