Then you most likely:
- don't have a common ground or
- you cut supply to the USB chip as well or
- Your power supply doesn't supply a stable enough voltage at low startup current.
If you use a 'standard' ATX computer power supply, they don't really work well at very low loads. See here for a description and solution:
https://mysite.du.edu/~etuttle/electron/elect62.htmI don't get it.
PSU is a dedicated 5V limited at 10A that can be regulated. I set it to 5.15V and have over 4.95V directly on the moonlanders.
I tried another smaller 4-pot hub that has a better layout, dual layer well grounded and I can see the + from the usb plug going directly to the 4 sockets and the switch just adds the ext power where I solder on my 5V.
I plug in only 2 MLs but still no devices found.
If I plug one ML directly in the Pi it works fine, apart from the p2p pool issue.
I have done the 2.1A USB hack in the pi by replacing R54 with 10kΩ.