Please tell me not to worry - powered hub

GarSpear · Sep 16, 2015

I bought the Inatek 5V/4A powered USB 3.0 hub (2A available to 4 USB 3.0 ports and 2A available to a USB designed for quick phone charging).

It felt and looked nicely made and worked well. It even had a groovy soft touch on/off button with power light led.

However I have just realised after 5 days of the hub being plugged in but not turned on, that when I went to work in the case (after first having switched off the PSU at the back of the PSU and pressing the power button) I noticed the standby lights on the motherboard and GFX card (I guess both are 5v standby) didn't go out.

A quick experiment revealed that the standby lights go out on the motherboard and GFX card as normal when turning the swich off on the back of the PSU. However with the hub is plugged in but switched off or on at the hub the lights to the motherboard and GFX card stayed on. In other words somehow the USB hub was powering the standby lights of the motherboard and GFX card.

I have unplugged and removed the hub because I have got a bit paranoid. If this is a normal feature of this hub, should I be worried that anything has been damaged. All seems fine but now I got doze eeby jeebies.

Put my mind at ease please.

InvalidError · Sep 16, 2015

It sounds like your USB hub has no power isolation switch between host power and its own power adapter, so your PC's 5VSB rail ends up back-powered by the USB hub.

It may or may not be a feature: this is handy for people using the hub as a docking and charging station for a smartphone, tablet, nettop, etc.: the device gets charging and external mouse, keyboard, display, etc. all from the same USB port.

jimmysmitty · Sep 16, 2015

Wait is the PSU switch turned off when this happens?

InvalidError · Sep 16, 2015

jimmysmitty :

That is exactly what it reads like:

when I went to work in the case (after first having switched off the PSU at the back of the PSU and pressing the power button) I noticed the standby lights on the motherboard and GFX card (I guess both are 5v standby) didn't go out.

And it seems like the USB hub keeps sending power through the host port even when the hub itself is switched off since he later says the hub's power switch has no effect - at least not as far as the motherboard and GPU standby LEDs are concerned.

jimmysmitty · Sep 16, 2015

I am assuming so but the wording was a bit off.

I have seen USB hubs keep power or cause other strange issues but never keep standby lights on the board on.

GarSpear · Sep 16, 2015

That is exactly what I am saying. Hub is switched off. Lights stay on. It is feeding the standby light or circuit of the motherboard and GFX card (my card has lights on the power sockets) as long as the ac/dc adapter for the hub is plugged in.

Computer seems fine. Could there be any damage?

InvalidError · Sep 16, 2015

GarSpear :

As long as the hub's power supply is putting out clean and stable 5-5.2V, it should be no more dangerous than the PSU's own 5VSB output when the PSU is plugged with its switch turned on.

GarSpear · Sep 16, 2015

ok thanks.

I don't like that idea. Off is when I click the psu switch off, not when Inatek say off is on.

Nice hub. I spose one possibility is to get another 5V4A power supply with same socket end. Hassle hassle hassle..

GarSpear · Sep 17, 2015

Right can anyone recommend a good powered USB hub? Cos I am sending the Inatek back.

The Inatek hub itself is lovely but I don't want a relatively cheap AC/DC adapter keeping my mobo live with 5v. That's the PSU's job as far as I am concerned. My computer my rules. I can live without the charging ports.

Presumably an AC powered 3.5 external HDD is fine to run from one of the inbuilt motherboard USB sockets? So maybe I'll just keep cables permanently connected to the rear for external AC powered HDD's... the only reason I like hubs is that they avoid constantly stressing the motherboard and case and external HDD USB connectors.

fisbuar · Sep 17, 2015

Hold on a minute here..
A POWER SUPPLY, in order to deliver its correct voltage uses a CONDENSATOR, which holds current for a time, before releasing it to the powergrid.
basicly its like a little bucket filled to the brim with "POWER", and only by adding a little more power, only the excess power, will be used and this creates a steady flow of power which does not vary too much, because PC hardware is VERY sensitive to voltage variations, the CONDENSATOR, prevents too high, or too low voltages... in order for the CONDENSATOR to even out the voltage output for the computer to use, it must HOLD a portion of power.

Basicly what i'm saying is, the CONDENSATOR, will keep a portion of the power, even AFTER the POWER SUPPLY has been turned off.

This means two things.

1: minimal powerconsuming components, and LED's will still be powerd a few seconds up to several minutes after power is removed from powersupply, depending on the powersupply.

2: In any case where you are doing "maintenence" inside the Computer chassis, you should wait approximately 5 minutes, AFTER switching OFF, or UNPLUGGING the power supply from its powersource.

In a short simple summary... your Powersupply, is powering your motherboard a while after the powersource is severd. ( which can make your standby lights to stay on).

A condensator is basicly a mini battery, which holds power for a small amount of time.
https://www.google.com/search?q=Condensator&source=lnms&tbm=isch&sa=X&ved=0CAcQ_AUoAWoVChMImp6Jh7X9xwIVQdQaCh0IFApx&biw=1920&bih=969#imgrc=EzgqtEOo9syN6M%3A

If you still Insist on changing USB hub, i strongly recommend this one, which also helps you hold your mouse coord, to avoid it being stuck or in the wrong place.
http://www.amazon.com/ROCCAT-APURI-Active-Mouse-Bungee/dp/B0071JXE0G

GarSpear · Sep 17, 2015

I don't see where the reply button is... to the person who has kindly replied..

You misunderstand I think..

When this hub is plugged in, even when the hub is turned off at the hub. And even when I have turned off the PSU or diconnected it completely AND pressed the PC on/off button to dissipate charge in the capacitors of the PSU/wherever.. normally I would expect to see all lights go out. With the power supply to this hub they do not. This hub back feeds its voltage into the USB hub.. I don't know if other USB hubs do this? I don't think so because I have never noticed this 'feature' before. As has been suggested this is likely a feature to allow charging of devices like phones from the specific fast charging port wven when the computer is off. I do not like such a feature.. it concerns me.. I don't want my USB hub powering anything on my motherboard. Am I making any sense?

Like I said, lovely cute looking and well designed hub.. but I can't live with the always on feature that keeps my motherboard always on standby.

I am in the UK by the way, so the USB hub you recommend might not be available to me here.. I prefer to go with Amazon because they have good return policy and customer support.

GarSpear · Sep 17, 2015

In other words, it is not a 'condensator' issue..

If I plug in the AC/DC adapter to the hub, when the standby lights are off and the PSU power supply disconnected, this hub will turn ON the standby lights on my motherboard etc and they will stay on until the power adapter to the hub is disconnected.. the switch on the hub does not turn off the power to the hub. The hub power AC/DC adapter feeds standby power to the motherboard...

fisbuar · Sep 17, 2015

Leave the PSU unpowerd for 30 min, if motherboard lights are still powerd, then yeah this might not be too good.
And btw that USB hub actually is on amazon

GarSpear · Sep 17, 2015

I did that dude. The lights go out when hub adapter is unplugged and PSU discharges. I can of course ensure discharge by pressing PC on/off button whilst PSU is switched off or unplugged and hub is unplugged. When the AC/DC adapter for the hub is plugged in the lights go on even if the PSU is disconnected from the mains. Thus the hub AC/DC adapter is feeding the ports with 5v. This is probably to allow charging when PC is off. But I don't want that feature.

Thank you by the way I shall have a look.

GarSpear · Sep 17, 2015

Actually I have just realised all my powered USB hubs have the same effect.

If I turn off PSU by unplugging and discharging (pressing on and off button on PC) the standby lights go out.

If I turn on AC/DC supply to hub they stay on even if I do the above.

HOWEVER! If whilst the PSU is still off I then unplug and plug back in the USB cable of any of my powered hubs the lights go off.

It seems once the PSU has been switched to on, the AC/DC power adapter keeps powering the circuit until it is unplugged at the mains or at the usb. But once the PSU is switched to on and plugged in, the lights come on again as you would expect. However, switching the PSU again needs the hub to be unplugged either at the mains or via the USB.

Do all computers have standby lights on the actual motherboard?

And should the ram or system light be on when the PSU is switched to on but the PC is turned off?

InvalidError · Sep 17, 2015

GarSpear :

Most motherboards have some form of 5VSB indicator as a courtesy to remind people to physically turn power off before messing around inside the case.

As for the other leds, that varies depending on manufacturer.

fisbuar · Sep 20, 2015

Sounds like the Power adapter keeps a relay open in the PSU.

https://www.google.com/search?q=relay&source=lnms&tbm=isch&sa=X&ved=0CAcQ_AUoAWoVChMIlNfH9MCFyAIVBX0aCh1hCgRQ&biw=1920&bih=969#imgrc=nEq18auHTcDO_M%3A

The adapter might be feeding the condensator, which again holds the relay open/on.

In any case, i do not think its very good for your Mobo.

Please tell me not to worry - powered hub

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