AC power light comes on when running off battery...

[Mightyena]

Hi, sorry to keep having to create these threads but it seems my somewhat sizable collection of Thinkpads are all developing problems these days!

Anyway, the current culprit is an X200 frankenpad system (X200 T9550 mobo, in an X201 base and 1280x800 X201s lid).

The problem is that for some reason, it thinks the AC adapter is constantly plugged in. If there's only the battery present, the AC light is on, and the battery LED and power manager (and the windows battery monitor) all say the battery is "charging", although the percentage is going down. The OS is Windows 7 professional x64, although I don't think it's an OS issue as the LEDs behave like this even if the unit is off.

I should also mention that it isn't an issue with the battery as all the X200/1 batteries I own behave this way in this system, and the battery I am using works fine in my X201

It's not really a deal breaker, but I would appreciate any ideas how to fix it, since other than that this motherboard has been spectacular, running at 2.6GHz under full load (ORTHOS or prime95) it barely pushes 55C running at 0.975v, and I was hoping to get a Hydis screen for it at some point.

Here is an image of power manager while the AC adapter is unplugged (Laptop is running off battery only): http://hostthenpost.org/uploads/cc1c067 ... d1fbd7.png

Thanks in advance for any suggestions,
James

[brchan]

Very odd. I might try a bios update to see if it fixes the issue.

[Mightyena]

Thanks, I'll try a BIOS update and see what happens

EDIT: I tried a BIOS update, and the problem still persists... I have to say, I'm completely stumped by this one!

[UkeDog]

Mightyena, I realize this thread is old, but I'm curious if you got to the bottom of this?

I'm having the identical problem with a T61 that I resurrected from storage, installing a new (3rd party) battery.
It operated fine running from the battery when I first got it; however, I noticed the AC power LED was always lit.
The battery has drawn down to 1% despite resuming AC power, all with the system reporting that the battery is charging (it has not).

I have no other battery to compare against, so I'm wondering which of these is more likely:
- the new battery is faulty, basically does not recharge
- the T61 charging circuit is faulty

Notes: T61 has the latest bios (2012 vintage), 4GB ram, and is running Windows 10 64-bit fine with no other problems noted

TIA!

[RealBlackStuff]

Mightyena hasn't been on the forum for over a year...
Check the DC-connector, these occasionally go bonkers.