Hello,

I have been looking on ebay for a IBM thinkpad, and i was wondering if my ac adapter from my dell inspiorn 3500 would work with the thinkpad T23, should the ports match.

No. They will NOT match. And no, the voltage and amperage is different. You want a 16V 4.5A power adapter which you can find for cheap on eBay if you are patient.
The amperage is the critical component.
But the plug and socket definitely will not match. I have one of each on my lap as we speak, just to be sure.
The Dell is usually 90 Watt, 3.5 Amp, 20 V, or sometimes 90 Watt, 4.5 A, 20 V.

The Dell 3500 adapter is : 18-20 V - 3.5 A - 75 W - See HERE

The Thinkpad T23 adapter is : 16 V - 3.5 A - 72W - See HERE

If it was my risk, I`d go for it.

This should not be taken as a Techspot recommendation

that you go for it.

I am sorry, but that is a UK website describing parts for the European market.
Take a look at the Dell website in the use for the Dell Service Tag for that model. or on the Lenovo Website, using the IBM type number.

The AC adapter for the Dell 3200, 3500, 3700, 3800, 4000, 4100, and 4150 solde in USA, is
90 watts, 20V, 4.5A.
The adapter for the Thinkpad T-23 sold in USA is
72 watts, 16 V. 3.5 A.

If the connectors were the same, they would both work for a while, but you could have batter damage, and ruin the charging mechanism.

The problem is that the connectors are not the same. The Thinkpad socket and pin are smaller. The Dell plug cannot fit that socket. The Thinkpad plug cannot fit the Dell socket.

As I reported, we have both of them here in our shop for physical comparison, but if Quantex Fox lives outside the US, and compares by Service Tag for that market, he may find there is a difference.

You don't risk much except the money spent for something that doesn't work, short term, but you risk the charging assembly and the battery life, if working, long term.