PS2 not playing CDr's

[jimmy154]

Hello everybody.
I have recently had the messiah 1 chip put in my version 3 PS2 and after only 3 weeks of it being in there the console has decided not to boot CDr's anymore. It keeps coming up with disc read error. It still plays DVDr's most of the time anyway but some of the games I have are on CD. Do I need to calibrate the laser of is it trying to tell me that it's had it! Do you think it just needs a clean or something? Also, the DVDr's that work are on Traxdata discs which I have bought off of one of my friends but when I have tried to back-up on my own using Bulkpaq generation 4 discs and Princo discs they have not worked. Any ideas?
It has cost me a fortune to get it chipped, infact almost as much as a whole new console costs but please be brutal with you answers coz I'd rather know than waste more money.
Thanx Guy's
Jimmy