Thinkpads Forum

I have been using a 2-pin, 65w, 20v (92p1160) adapter for 4 years. I found it was broken last week so I bought a new one (original Lenovo product) from Amazon. When I finally received it, I found it was a 3-pin, 65w, 20v adapter (92p1158). It should be fine, right? so I started using it.

But somehow, it works okay only when I close my laptop and put it aside. When I open my laptop and actually use it, it stops charging within minutes..... I am sure my battery is fine. Why is that?

If I have to use a 2-pin, 65w, 20v adapter, where should I get it? Amazon listings are sort of ambiguous when it comes to the descriptions.

Basically 2-pin is for USA, 3-pin for the rest of the world, where they use a separate ground.
It makes no difference really which version you use, both should work here.
3-pin in USA is just annoying because there are so many outlets with only 2 pins.
If your T61 has Intel graphics, then the 20V 65W is fine.
But if yours has nVidia graphics, then you need the 20V 90W version.

There are four OEM versions of the 2-pin and the 3-pin adapter. IMO, not all the manufacturers are the same. I discovered what was in this thread:

http://forum.thinkpads.com/viewtopic.php?f=29&t=66692

Actually the adapter itself is double grounded, so adding the third ground wire is redundant, but some countries have old laws on the books and have never removed the requirement that electronics be grounded, so making 3prong adapters was necessary. The main reason people don't like the 3prong is the cord is bulky, but also, the original adapters that shipped with these systems are different then the genuine replacements lenovo sells. The quality isn't as good. I've found some original ones that are brand new, just as they shipped with a new laptop, as well as some excellent used ones. If you want one you're free to drop me a PM. As far as buying new ones online, I think you'll find they are all the replacement type, not original. A few months ago one of our regular members and I combined our efforts and purchased a huge quantity of adapters, I did look at nearly every amazon and ebay offering at the time. All the new ones were 3prong replacement types.

TuuS wrote:Actually the adapter itself is double grounded, so adding the third ground wire is redundant

Only the 2-prong version is doubly insulated, and my experience is that it still is not as good as grounding. I used to get various ripple effects on the LCD, small electric shocks from the corners of the laptop or through fingerprint reader while using the 2-prongs which I never experience with the 3-prongs. It may have something to do with being on a 230V grid, maybe for the 110V grid the 2-prongs are good enough, I don't know.

TuuS wrote:The main reason people don't like the 3prong is the cord is bulky

Another reason that I prefer the 3-prong is that the cord actually sits well in the socket. I've seen too many loose sockets which don't hold the 2-prongs well, and they keep falling out.

TuuS wrote:but also, the original adapters that shipped with these systems are different then the genuine replacements lenovo sells.

Interesting. So Lenovo does not sell the 2-prongs separately, or are there other differences? What is the difference in quality you observed?