Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

My Laptop is Lenovo Thinkpad T400 with Ubuntu 12.04 and Windows 7


  1. When I use Ubuntu 12.04 (and 10.10 previously), every now and then, the wireless connection drops, and then no wireless networks are detected.

    Things are similar in Windows 7. When wireless connection drops, it says wireless adaptor not detected.

  2. When the problem happens, if I restart the laptop, the wireless connection will be back, regardless of which OS it is.
  3. The problem happens more often when I move my laptop around, but also happens when I keep it at the same place on my desk.

  4. The problem didn't occur during the first year of use.

Some advice I found:

  1. Some said it might be because the wireless adapter was loose. But I don't know how to find the wireless adapter in my laptop and how to detach and re-attach it. Can someone give me adivce?
  2. Some said that it might be because the power management disable the wireless adapter to save energy. I keep my battery charged at 50~60%, and the problem occurs when the laptop is in power not just when it is on battery.

I wonder if you could give some advice?

Thanks and regards!

share|improve this question

Here is the service manual for the T400. Page 97 deals with the location and removal of the Mini-pci wireless card. It references other steps you must go through first to get to it.

This issue was addressed a couple of months ago on the Lenovo forums for a user, and there were two possible areas to address the wireless card power management, and disabling it.

Resolving Power Management Scenario 1

If you are in in 'Energy Star' mode for instance, if it can't find a wireless network in X amount of time it just turns it off. Setting to "Max performance" or disabling the setting to allow the wireless card to save power.

  • Press the blue ThinkVantage key
  • From "Resource Center" menu, click "Wireless" and then "Find Wireless Networks". The Access Connections window will pop up
  • Go to "Options" tab and uncheck the "Allow the wireless LAN radio to be turned off when inactive." box

Resolving Power Management Scenario 2

If the steps in scenario 1 above did not resolve the adapter from being powered down during inactive periods and dropping connection, try the following:

Control Panel --> Power Options --> Power Manager (on the left side in red) --> Advanced Settings --> PCI Express --> Link State Power Management. Change both Battery Settings and AC Settings to OFF.

Now, apparently there also might be an issue with the Lenovo wireless connection manager... and this same forum post addressed this as well.

Resolving Windows / Access Connections Conflicts

You can only have one wireless client software active.

  • If you want to use Windows to manage wireless, then uninstall Access Connections.

  • If you want to use Access Connections, don't create wireless connections through Windows, use Access Connections.

  • When Access Connections attempts to connect, it automatically turns on the wireless radio, while Windows wireless does not.

All that is from here.

share|improve this answer
Thanks! I mainly use Ubuntu instead of Windows, and have the problem. and the problem occur while the laptop is on power instead of on battery. So I think the link to the forum post doesn't apply, I will try to understand how to open my laptop and look for the wireless adapter. – Tim May 27 '12 at 1:50
In the T400 manual, on page 97, it is "1090 PCI Express Mini ardforwireless LAN/WiMAX", and on page 100, it is "1100 PCI ExpressMini Card for wireless WAN". I wonder which one is my wireless adapter? Why did you say the first one, not the second one? Thanks! – Tim Jun 2 '12 at 11:14
@Tim It was a toss up. Only you would know which was actually within your laptop... there are essentially three different kinds of Mini PCI wireless cards. Two with one blade design… note the location of the notch there, and one half-width… note the different notch location. Again... only you would know which, but having the manual, I assumed you would find your way to the right card regardless. – Bon Gart Jun 2 '12 at 14:43
Thanks! What does "one blade design" mean, and is there double blade design? – Tim Jun 2 '12 at 18:08
@tim that was more my phrasing to describe the location of the notch on the contact blade. With the two wider cards, the notch is all the way to one side, making it essentially a single blade of contacts... where with the narrower card, the notch is closer to the center of the card, dividing the contacts into essentially two blades. – Bon Gart Jun 2 '12 at 18:11

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .