why disk read error? sony fault?

[GameGUy999]

hi i had use and sell some of my ps2 because of disk read error. i was wondering is it sony fault that have something defective or is it my fault for doing something wrong? i play my original game and backup normally and for a while the ps2 give me disk read error. the two that did that to me has a model of 30001 and now i had bought a new one 39001 and it seem to work longer than the 3001 wiht no problem accure yet.