USB 3.0 7-way Hub — Beware!

I get a lot of stuff on line, and much of it is really cheap. This particular USB Hub seemed to be just what the doctor ordered. So I ordered it. £8? You can’t go wrong.


It looks nice enough. A mains adaptor so that you have extra power and you won’t put a strain on the USB system in your computer. A nice flat cable (which turned out to be a stroke of luck, at first!), and 7 outputs for all your accessories.

I tested it on an old computer, which had an add-on USB3 board, and the computer wouldn’t boot! However, when I disconnected the mains power from the hub, and allowed it to be powered entirely by the computer, it worked just fine. But the computer I bought it for was my new build, a Mini-ITX computer which only had two exposed USB3 sockets, one of which was dedicated to the CD/DVD-RW drive. You can see the flat blue cable where the hub is plugged in at the back.

Computer mounted on wall. Wireless dongle plugged in at top left.

Computer mounted on wall. Flat blue cable connects to USB hub.

The reason that the Hub only worked if I removed its power supply, was because it was backpowering along the +5v supply lead. I’ve read that it can be a serious problem with some types of motherboard, particularly the Raspberry Pi. There is a simple cure for this, made simpler by the fact that the cable was flat. I stripped off a little bit of the outer insulation from the middle of the lead, and cut the red wire. Then I soldered in a Schottki Diode, which enables the current to flow one way only, and tape it all up. Sorted!

Delayed Bootups

However, the end of the problem was but temporary. More recently, I started to get weird messages on bootup, and depending on whether I booted into MX-Linux or PCLinuxOS, other things like a much delayed bootup, or even the keyboard and mouse becoming unresponsive when I finally got to a desktop (PCLinuxOS), or only the three USB sockets nearest the end working.

The actual chip that divides up a single USB port into many, is 4-way. To get 7, three of its outputs go to the first 3 sockets, and the other one goes into a further chip. When I managed to get PCLinuxOS started with the keyboard and mouse working, the Kde Info Centre showed me that I had a 4-way hub, but there was something plugged into it which was returning some obviously broken data. I couldn’t get any info from MX-Linux at all.

The unit hasn’t been bashed about, it’s actually been blutacked to my desk, so this is very disappointing. I’ve splashed the cash on an Anker model, with 7 ports plus 3 more high-powered USB charging ports, silly money but I hope it works without backpowering or burning out!

Addendum: Anker model waste of money

After a short time, the Anker model started behaving erratically. In this case the problem seems to be the power supply. And Anker found a simple solution to the problem of backpowering: don’t connect the power lead from the computer. The upshot is that if the power supply switches itself off for some reason (which it does all too frequently) the 7 hub sockets are totally useless. As of course, are the three charging sockets. In the end I spent a fiver and bought a cheap, unpowered, 4-socket USB3 hub, a bit restrictive, but at least it works, reliably.

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