W520 doesn't charge and when turned on, if I disconnect the power cable, it shuts off

[Thinkpadder0]

Help? Just started happening, was charging fine. I have about 70% battery. If the system is running and I disconnect the cable, it's shutdown. Doesn't work with the cable connected and no battery (strangely, starts up and shows a message about battery being critically low, even when disconnected.

What do you think? Charger issue? Or something inside the notebook itself?

[Tim-ANC]

If I understand you correctly, it does work with battery installed and charger connected.

If so, you have a bad battery. It is giving you a false indication that it is at 70%.

[jcvjcvjcvjcv]

I think death battery.

Just curious; 9 cell one?

[ajkula66]

Doesn't work with the cable connected and no battery (strangely, starts up and shows a message about battery being critically low, even when disconnected.

Presuming that you're using the correct 170W adapter and given what you've written above there might be a blown fuse on the motherboard or something along those lines. Do you have access to a *known good* battery that you could test your machine with, or another system to test your battery in?