Question Midi device frequently disconnects and shows as 'not recognised' in Windows, but it works fine on Linux ?

[JamesC01]

I have a Novation Launchpad MK II MIDI Controller, and the USB port on it is slightly inconsistent.
If I wiggle it, it will disconnect for a moment. On Windows, this causes a complete disconnect, and when I reconnect, Windows says it's 'not recognised', and device manager shows "device descriptor request failed".

To get it to work, I need to disconnect and reconnect the device a bunch of times until it reconnects again, and even then the slightest bump will repeat the cycle over and over again. I tested it on my chromebook, though, and it works fine for the most part. When I plug it in, it connects perfectly fine, and when I wiggle the cable, while it might disconnect for a second and leave a hanging midi note, it reconnects fine once I stop wiggling the cable, pretty much instantly.

Why is this? Does Linux have more tolerance for usb devices disconnecting for a moment, whereas Windows treats any disconnect, even the slightest fraction of a second, as a full disconnect? Is there anything I can do about this?

 

[Phillip Corcoran]

You've tried a new USB cable ?

 

[Paperdoc]

You describe an intermittent connection problem. That could be at either connector for the USB cable - at the Launchpad end, of the computer end. You do not make it clear at WHICH end it disconnects when you wiggle it. IF it is always at the computer end, try moving to a different socket to see if that makes any difference. If it does, then the problem is in the SOCKET you have been using on your computer.

Then try this for your wiggling actions. At the Launchpad end, grasp ONLY the heavy larger body of the connector on the end of the cable and try to wiggle the plug in the socket, and NOT wiggle the flexible cable. Try the same thing at the computer end of that cable. If either causes your problem, the trouble is in the socket or in the contacts of the socket and cable plug.

If that does not clear up the source, try this instead at each end of the cable. Hold the cable PLUG in the socket as securely as possible so it does not move. Then grasp the flexible CABLE near the plug and move it. Maybe try a few different spots along the cable, from right next to the plug body and on outwards from there. If that causes your problem, you have a bad wire or two inside the CABLE and the solution is simply to replace the cable.

If these tests say it is NOT an internal cable problem, but more likely at problem in the connection between socket and cable plug, then replacing the cable may be the solution - depends on whether the issue is contacts in the cable plug, or in the sockets. Either way, a relatively cheap part replacement.

If that does not do it BUT you can make the problem happen by wiggling ONLY the cable PLUG in the socket on the Launchpad, then the problem is likely inside the Launchpad unit - either the contacts of the socket, or a loose connection of the socket to the motherboard inside the Launchpad unit. That would require opening up the unit to search for such a trouble source.

Oh there's another possible source entirely - power supply. The Launchpad unit gets all its power from the computer USB port you plug it into. An older USB2 port can supply power at 5 VDC up to 0.5 A. A newer USB3 port can supply more amps - up to 0.9A - so you might try switching to a USB3 port in case that helps IF you have one. But also, IF you are NOT plugging into a USB port directly on your computer, but are using it through a USB HUB, then the OTHER items also plugged into that Hub are using some of the power available. In that case, try plugging the Launchpad unit directly into a computer USB port, NOT through a Hub.