@awtpling I tested the USB hub UH700 again. With and without its own power supply. On different machines/PCs. With Windows and Linux. The hub is not recognized/seen anymore. USBDeview from Nirsoft...

I have a USB-Hub UH700 S/N 216718000115x V2.0. It doesn't work anymore. Suddenly. How can I test it if it's defective? I tried on different computers, but with a simple mouse plugged-in on differnt...