T400 reboots when disconnected from AC power

[baertracks]

I recently purchased a used T400 to take to Africa for a friend. In doing a bit of testing I discovered that it reboots whenever I disconnect the cable from the back of the laptop.

The battery is good (I've tried several). The power adapter is good (I've tried several). An Internet search didn't turn up much, but appears to indicate that this is a problem with the motherboard, e.g., some sort of voltage-related issue.

HOWEVER, I discovered today that the laptop, when in safe mode, does not reboot when disconnected. That would seem to indicate that this is a Windows problem (or some other program interference). Correct? I have not loaded any additional programs myself, but it may have come with some additions.

My plan is to re-install windows (7 Pro 64) and then retest. But first, I thought that I would put this on the forum to for possible comments and advise from anyone who has previously run into this issue.

Thanks,
FRANK

[baertracks]

I recently purchased a used T400 to take to Africa for a friend. In doing a bit of testing I discovered that it reboots whenever I disconnect the cable from the back of the laptop... My plan is to re-install windows (7 Pro 64) and then retest. But first, I thought that I would put this on the forum to for possible comments and advise from anyone who has previously run into this issue.

As a follow-on to this issue, I can now report that sometimes the reboot does not begin immediately but rather 5 to 30 seconds later.

I re-installed windows (7 Pro 64), and that that did NOT fix the problem. I'm now thinking that this must be some sort of motherboard problem.

FRANK

[Neil]

...when in safe mode, does not reboot when disconnected. That would seem to indicate that this is a Windows problem...

Interesting observation, this. What safe mode does is load OS without loading most of the device drivers, so it may not be the OS that is causing the problem, but rather a device driver. If that is the case, re-installing Windows won't fix the problem, because the same device drivers that were there before will be installed again.

This problem is very likely to be a system board issue, but you haven't really ruled out the OS (or drivers at least) until you boot up a different OS (maybe a Linux LiveCD) and see if the problem persists.

[baertracks]

...when in safe mode, does not reboot when disconnected. That would seem to indicate that this is a Windows problem...

Interesting observation, this. What safe mode does is load OS without loading most of the device drivers, so it may not be the OS that is causing the problem, but rather a device driver. If that is the case, re-installing Windows won't fix the problem, because the same device drivers that were there before will be installed again. This problem is very likely to be a system board issue, but you haven't really ruled out the OS (or drivers at least) until you boot up a different OS (maybe a Linux LiveCD) and see if the problem persists.

Thanks for the clarification between loading the OS and loading the OS + drivers.

Since the Windows 7 installation was done from separate disks (the first by the eBay seller, and the second by me) I don't see how/why both installations could/would end up with the same driver problem. I did not load any additional drivers (or ThinkPad add-ons) to the newly installed system. I agree that this is probably a system board problem.

At this point the question is moot, as the eBay seller has accepted to refund my purchase, so this laptop is heading back to the seller.

Thanks!
FRANK