Differences between T20 T21 T22 T23

[t20user]

I am thinking of getting a(nother) thinkpad for my parents. I would like to get another T20 but I cant help but think there are some deficiencies in the T20 that were fixed in later models.

2 things I really do not like about my T20 are the loud fan, and the white spots on the LCD from pressure on the lid.

I could not find a good comparison doc if someone can point me.

[erik]

the T20/21/22/23 hardware maintenance manual is the best source for information regarding specifications and physical differences between the four models.

the IBM certified used notebooks department is a great place to shop.   if you don't like a model for any reason (including physical condition) you can return it within 7 days.

-erik

[beeblebrox]

white spots on the display can occur on any LCD screen and any computer, if pressure is applied on the LCD from the back, so that the background diffusor foil is damaged.
My T20 display is 4 years old, had never any pressure on the lid, and therefor looks like brand new.