chip is damaged

[NoNo9]

If the only problem you have with your PS2 is that laser then don't waste money, just replace it (it's 50 bucks, including shipping at rich's and the installation of the laser unit is a breeze, unless you can't do anything like that).
As others here said, slim ps2s have huge problems with backups and older ps2s just have no additional value at all, it's really the same thing.
With the money you save you could get a large HD to use with HDloader or get a Gamecube which cost nothing and can finally run backups as well (It's an excellent choice if you like platformers)