Do you still have the power supplies for both computers ? Are you any good with a soldering iron ?
If the two power supplies have essentially the same output ratings - say within 1/2 V and 1/2 A - then you could just cut the connectors off, a few inches back from the end of the cable and put the 1525 terminal on the 2200 lead. Or be even more clever, if you still want to run both computers and solder both connectors to the one output lead. Obviously you could only use one computer at a time.
You would need to be careful about the polarity of the wires as you soldered them together, but the internal leads are normally a different colour, or one is striped, and you would need to be careful about insulating your joints.
As you say, both machines are out of warranty so butchery of this sort won't impact on warranties ! Have you considered just buying a replacement charger, they are not that expensive ?