ac adapter 56w vs. 72w

[meeotch]

I recently bought a t43p off Ebay, and it came with an 02k7006 (FRU 02k7007) AC adapter, which is 3.36A (or "56W", as given in various spots on the internet). My old t42p came with a 08k8208 (FRU 08k8209) AC adapter, which is the 4.5A (72W) version.

Searching these forums, I found one thread indicating that the 56W model is for "lower power thinkpads". The lenovo site lists the 72W model as being t43p compatible, but has no similar information on the 56W model.

Can someone point me at a spec sheet or other info that says whether it's safe to use the 56W model with a t43p? Has anyone had issues with their thinkpad being "underpowered"?

[rkawakami]

I don't believe that there ever was anything published from the factory which says what would/could/might happen if you use a 56W (3.36A @ 16V, so really it's like 54 watts) power supply on a system which is rated for a maximum of 72W (4.5A @ 16V). Conventional wisdom says that several things may result:

- the laptop could be underpowered (receive less than the 16VDC it should get) if stressed with too much work; this might lead to strange operations or data loss
- the power supply could overheat/burn out
- nothing detrimental will occur

The best source to see what type of power supply the laptop was designed for would be to look at the label on the bottom of the system. It will have the maximum current spec, usually printed right on the big IBM label. As long as you use a supply which has a rating equal to, or more than, what's printed on the laptop, you will be fine. You can also check the "tabook" files as they will generally list what type of supply was provided with the system. For the cost of a 72W power supply, ~$10 to $15 on eBay, I'd simply replace the 56W unit. Keep it around if you have any or are planning to get, systems like the X2x or 600-series.

[exTPfan]

Your T43 should definitely have come with a 72W adaptor, so you have a right to complain.
That said, many of us run T42's and T42p's with 56W adaptors from older Thinkpads without problems.

[mpcook]

I have had a 56W unit that I was using interchangeably with a T40, T23, and X32. I noticed it seemed to get hot, it finally died. I don't know what caused this to happen, but I stopped using 56W units with the T2* or T4* machines.

Mike