Need help determining polarity of Thinkpad Lenovo power adapter.

[Evil Lurker]

Ok so I aquired a Thinkpad Lenovo... its a nice core i-3 model however, I did not aquire the PSU adapter. I figure I can charge it up with another power supply brick and jury rig an adapter, but I don't know if the center or outside of the jack is positive or negative, nor do I want to risk damaging the laptop.

Unfortunately there are no standardized markings as to determing the polarity on the laptop itself, and since I do not have the original PSU, I have no way of determing what is what.

The only clue is on the laptop there are markings that look like this:

____
-----

And oh yeah it uses the standard 20v 3.25/4.5a brick.

I figure I could open it up but that'd be a big PITA.

[yyonline]

Re: Need help determining polarity of Thinkpad Lenovo power adapter.

Assuming it uses the same connector as my work T410, the outside surface of the barrel is negative. The inside surface of the barrel is positive. The center pin is a data connection to verify the adapter is genuine.