juan2003
Posts: 10
Joined: Thu Oct 11, 2012 12:49 am

Problem with Powered USB Hub. Please help!

Thu Oct 11, 2012 1:06 am

Hi,

Im a newbie with the raspberry pi (got mine yesterday) and Im planning to create a media center with it. For that I would like to attach a 500GB usb hdd that I already own.

Right now Im trying xbian but I already tried raspbmc and the same thing happened. Im using an 8GB SD for the OS, a 1.0A cellphone charger to power the pi, samsung lcd tv for display (hdmi).

For what I read I need a powered usb hub in order to power the usb hdd, so I bought one. I bought a "soyntec" powered hub with 7 usb ports (Model Nexoos 395, just for the record).

If I connect the keyboard into one of the pi's usb ports and the hub on the other (without anything plugged into the hub and without powering the hub), everything works well. If I add a 16GB pendrive in the hub (wihtout powering the hub), the pi recognizes the pendrive and works fine. If I unplug the pendrive from the hub and I plug the hub's power cord in order to get it powered (without plugging any usb device, just the hub to the pi), everything works well.

The problem comes when I try to plug anything into the hub after is powered. If I plug either the pendrive (which worked in the hub before powering the hub) or the usb hdd, the screen starts to "flicker" (black screen, back to normal for a second, black screen, and so on).

So the problem seems to be if I plug something into the hub when the hub is powered.... because if the hub is not powered, it seems to work. But if I dont power the hub I wont be able to use my hdd which is my objective.

I would really appreciate it if you could help me with this because all the uses that I thought for my pi rely on the usb hdd (media player, torrent seedbox, NAS).

Thanks in advance, and by the way excellent job with the PI, you are really inspiring the next generation of engineers. I wish I would had one back when I was on school, this is a great thing.

Juan

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malakai
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Re: Problem with Powered USB Hub. Please help!

Thu Oct 11, 2012 1:51 am

It has to be a power issue with the hub in some way I don't know the electronics side but it has to be feeding power through. Are you using HDMI is probably one question that needs to be answered.

A good powered hub shouldn't back feed power to the Pi are you using the port in the back to connect it to the pi (seems like a dumb question) but if that's the case I would try just powering the hub and connecting the pi without attaching the power to the pi directly. Does the pi power on? If it doesn't power the pi it could still be pushing power just not 5v 1a.
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juan2003
Posts: 10
Joined: Thu Oct 11, 2012 12:49 am

Re: Problem with Powered USB Hub. Please help!

Thu Oct 11, 2012 11:33 am

Thanks for the reply. Im using an HDMI cable to connect to the tv, but I think that works fine because if I dont power the usb hub or if just dont use it at all the rapsberry pi works fine.

About powering the pi with the hub, if I just plug the hub to the usb ports it doestn power the pi. I think that the pi have some diodes to prevent current coming in from the usb ports (I dont know anything about electronics, I read this on a forum). If I use a usb-microusb cable from the hub to the pi's power connector, the pi starts, but it flickers the same way I described before...

What I dont understand is, if the pi has something to prevent (I think they are diodes) current coming in from the usb ports (I tried this as it doesnt power the pi if I just connect the powered usb hub to the pi's usb port), why should feedback power from the powered hub affect its behavior? Because if I dont power the hub (I use it as a normal hub without powering to the electricity) the hub works fine with a usb stick.

Is there any walkaround this? Because the usb hub costed me $30... the half of the price I paid for a raspberry pi + shipping + taxes... and the raspberry pi worths a loooooooooooooot more in my opinion. It doesnt feel good to buy another $30 powered usb hub :)

Thanks!

juan2003
Posts: 10
Joined: Thu Oct 11, 2012 12:49 am

Re: Problem with Powered USB Hub. Please help!

Thu Oct 11, 2012 9:50 pm

It finally worked!!!

Im a bit ashamed of the problem... the power cord of usb hub was not tight at the wall plug... so it was kind of doing an on/off all the time, I changed it from place and its working! Thanks to all

Another question, now Im trying to use my usb hdd but xbian doesnt seems to see it. I did a tail to /var/log/messages and this is what it says:

Code: Select all

Oct 11 21:30:13 localhost vmunix: [  341.179742] hub 1-1.2:1.0: USB hub found
Oct 11 21:30:13 localhost vmunix: [  341.210156] hub 1-1.2:1.0: 7 ports detected
Oct 11 21:30:14 localhost vmunix: [  341.512875] usb 1-1.2.3: new high-speed USB device number 37 using dwc_otg
Oct 11 21:30:14 localhost vmunix: [  341.624065] usb 1-1.2.3: New USB device found, idVendor=1058, idProduct=0704
Oct 11 21:30:14 localhost vmunix: [  341.638847] usb 1-1.2.3: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Oct 11 21:30:14 localhost vmunix: [  341.654590] usb 1-1.2.3: Product: External HDD
Oct 11 21:30:14 localhost vmunix: [  341.671874] usb 1-1.2.3: Manufacturer: Western Digital
Oct 11 21:30:14 localhost vmunix: [  341.687920] usb 1-1.2.3: SerialNumber: 57442D57584D3430394E3933313130
Oct 11 21:30:14 localhost vmunix: [  341.712447] usb-storage 1-1.2.3:1.0: Quirks match for vid 1058 pid 0704: 8000
Oct 11 21:30:14 localhost vmunix: [  341.742670] scsi101 : usb-storage 1-1.2.3:1.0
So it looks like the hdd was recognized.... How can I use it (its in ntfs format)? Because I tried to follow some guides but they didnt worked. Should I mount it, how can I know which device it is?

I tried "mount -t ntfs-3g /dev/sda1 /home/mount1"

But I get:

Error opening '/dev/sda1': No such device or address
Failed to mount '/dev/sda1': No such device or address
Either the device is missing or it's powered down, or you have
SoftRAID hardware and must use an activated, different device under
/dev/mapper/, (e.g. /dev/mapper/nvidia_eahaabcc1) to mount NTFS.
Please see the 'dmraid' documentation for help.

Thanks!

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RaTTuS
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Re: Problem with Powered USB Hub. Please help!

Fri Oct 12, 2012 8:56 am

start with
sudo apt-get update
sudo apt-get upgrade -y
sudo apt-get install pastebinit
sudo fdisk -l | pastebinit
and post the link
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juan2003
Posts: 10
Joined: Thu Oct 11, 2012 12:49 am

Re: Problem with Powered USB Hub. Please help!

Fri Oct 12, 2012 11:42 pm

This is the output of fdisk -l: http://paste.debian.net/199734/

This are the last 150 lines of the /var/log/messages file: http://paste.debian.net/199732/

About the power, I meassured the voltage value (using the T1 an T2 points in the pi) before and after plugging the usb hub to the pi and the voltage is stable at 5V before and after... This means that the power is ok? Or it has nothing to do? I dont know almost anything about electronics...

Thanks!

theocoutu
Posts: 2
Joined: Mon Aug 06, 2012 12:17 am

Re: Problem with Powered USB Hub. Please help!

Thu Oct 18, 2012 11:49 am

What output does your HDD have? I have a 320GB HP PocketDrive, but the funny thing is that it has a printer usb port : http://img15.imageshack.us/img15/575/usbport.jpg and it came with a cable that splits into 2 usb male connectors. One goes into the host, the other goes into a power source, but if the HDD is plugged into both USB (Pi and Power) the connection powers the Pi itself, but the Pi doesn't recognize the HDD until I unplugged the micro USB from the Pi, leaving just the HDD.

sdjf
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Re: Problem with Powered USB Hub. Please help!

Thu Oct 18, 2012 2:55 pm

dmesg or /var/log/messages should show you the correct device name to use when mounting your HDD, but it might appear way above the last 10 lines displayed by tail /var/log/messages.

Try running "dmesg | less" or "less /var/log/messages" and then scroll through looking for device names to try with mount command. It might have assigned it something other than /dev/sda1 so of course, in that case, mounting /dev/sda1 would be a fruitless endeavor.
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RaTTuS
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Re: Problem with Powered USB Hub. Please help!

Fri Oct 19, 2012 10:20 am

download the latest weezy image that does not have a swap partition and you may have a better luck with everything
How To ask Questions :- http://www.catb.org/esr/faqs/smart-questions.html
WARNING - some parts of this post may be erroneous YMMV

1QC43qbL5FySu2Pi51vGqKqxy3UiJgukSX
Covfefe

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