T400 network cable unplugged even actually it's plugged

[adamf]

Hi guys,

I got a network cable unplugged issue from last week on my T400 laptop. No matter the network cable is plugged or not, it always report network is unplugged, and the two lights (green & yellow) at the side of the network cabel socket is always on even if the cable is unplugged. Plugging the same network cable to antoher laptop, no issue on network access.

Here are what I have tried:

1) upgraded the device driver (intel pro) to latest one, does not help;

2) Tried the repair function, but failed;

3) tried to restore to a point which is one week earlier than the date it stop working. did not fix the issue;

4) changed the Intel pro to 100Mb full deplex, does not work; but when change to 10MB full duplex, some web pages are accessible, but the data download is always stopped after a while. However, these two days this setting could not access web page any more. It keep acquiring IP address and always says no connection.

5) With Ubuntu 8.1, shows same issue.

I also tried the wireless to see whether can accesss the network, it even could not turn on. is the wireless and ethernet on same hardware card? now both wired and wireless out of work.

Please help to advise the possible causes, solutions or how to diagnose further, thanks very much,

Adam

[ExJamJus]

Correct me if I'm wrong but I don't think the LAN and WLAN are sharing the same hardware.

Try doing a Power Cycle (remove AC and Batt then hold power button for 15 seconds then put back AC and batt and see if it helps).

Tested with different LAN ports? Different network environment?

[adamf]

Thanks for the suggestion. Here's my update.

1) Tried to remove the battery and power supply and press the power button for more than 30s, but does not help.

2) Run Ubuntu 12.04, the wireless WiFi looks like can find some agent, but LAN could not access. I did not find where to configure the LAN settings;

3) Notice that even the network cable is unplugged, the two lights (green/yellow) are still on and always on. Does this mean the hardware of the LAN got issue?

Thanks,
Adam

[CorkyG]

Have you tried replacing the cable?  I've run into that occasionally, and network cable connectors can be bad.

[richk]

It sounds to me like the socket or the signaling chip is defective. Do you have warranty left?

[adamf]

Thanks for the suggestions. Here's my update:

1) tried on another cable, does not help. confirmed it's not cable problem since another laptop with same cable has no issue;

2) Uninstall all ethernet and Wifi dirvers, and re-install them. Now the Wifi works, but ethernet still have same problem.

So looks like the ethernet has some hardware issue. Warrenty has expired nearly one year ago.

Any other suggestions?

I'm thinking to opne the laptop to check the ethernet card, but do not know how to open it, anyone knows?

Thanks,

Adam

[lead_org Microsoft MVP Contributor]

You could also try an advanced mini dock with lan connector, this should tell u whether it is connector or the actual Intel lan chipset that is causing the issue.

[ColonelONeill]

Try resetting the BIOS to defaults. (Unset any BIOS passwords beforehand.)

[Mornsgrans]

Depending on the type and model of the router it is able to switch the ethernet ports to power save-mode.

Some combinations "Thinkpad vs router" do have problems with it. Disable the powersave - mode for the ethernet port(s) in the router-configuration and try again.