Quick Question Regarding Thinkpad AC Adapters

[Gilmore909]

Hello guys,

Well I have a T61 laptop widescreen, and recently my charger for some reason stopped working.

So I was wondering if any chance if I order another charger would it matter if it was from a T60 or R60 series laptop?

or does it have to be a T61 charger?


The reason I ask is because I've heard different models require different voltage/wattage to work.

Can anyone clarify on this?

thanks for your help!

[Harryc]

Doesn't matter. If you have a loaded discrete GPU machine and a dock, get a 90W vs. a 65W adapter.

[rkawakami]

Further clarification on your "different models - voltage/wattage" question:

Yes, there are quite a bit of differences in the various Thinkpad AC adapters over the years. Prior to the T60/R60/X60 systems, the DC output voltage for the adapter/chargers was 16V. With the 60 series systems and newer, the voltage was changed to 20V. There's also been (at least) two wattages for both the 16V and 20V versions. Depending upon the way the system has been configured (mostly due to the video chipset involved), IBM/Lenovo has specified a minimum acceptable power supply (65W vs 90W for 20V systems; 54W vs 72W for 16V systems). However, if you stick with the highest wattage supply in either voltage case, you will not go wrong.

In your specific question about T60 vs T61, both systems require 20V supplies. What does matter is what kind of video controller is in your T61. If it's an Intel GMA, then the minimum is 65W. If you have an Nvidia video chip, then you need the 90W supply. And if you have a dock as Harryc said, you'd be better off with the 90W supply regardless if you have the Intel video or not.

[Radioguy]

And if you have a dock as Harryc said, you'd be better off with the 90W supply regardless if you have the Intel video or not.

I didn't think it was an issue of being better off, but working at all. Will an X3100 T61 even work docked on a 65W? Is it safe?

[rkawakami]

Would it work? Probably. Is is safe? Depends on what you mean by that. Running a system on a power supply that cannot deliver the amount of current that is normally needed means that the power supply is being overworked or perhaps the laptop is undervolted.

Overworking the power supply typically means increased heat and a shorter lifespan. Undervolting the laptop could mean erratic operation, with the potential loss of data.

I don't have any experience with the newer systems to say that it will recognize that you are using a supply that does not meet the minimum current spec and thus goes into a lower power mode (throttling back on the CPU speed, turning off subsystems, etc.). If that does occur, then yes that would mean that your system is "safe" but certainly not performing as well as it could if you were using the proper supply.