I have a PS2 slim SCPH-79001 series and i hard-modded it, about 4 years ago, so that i could play burnt backup games on it. It was working without problem until about 2-1.5 years ago when it needed a lens change, because it burned, when it came back from the same workshop i hard-modded it, we still could play burnt backup games. But then about 4 month form now there was a voltage down in my house (which is common in my country) and the PS2 was ON and my brother was playing a burnt game (radiata stories) the PS2 was connected to a UPS(energy supply for blackout) so it didn't turned off in the mini-blackout that occurred when the voltage when down. The power when back to normal in half a second not even enough time to unplug an stuff so he keep on playing, but when he changed the scene in the game(entered a house) it took ages to load (about 8 minutes) which usually took less than a second as i burn the best quality disc at the best speed. Also loading backup games, became difficult and when they worked they were slow, games that usually were fast. then i tried with an original game and it worked just fine at full speed so i took it to the same workshop but they didn't have anyone who could help anymore as PS2 was considered outdated, so i took it to another one and they changed the disc rotor and a bus cable that when from the lens to the main-board; none of this worked and they said we needed an original lens which later came to my house to investigate on internet and turns out that the lens that they took out form my PS2 some years ago was a KHM430C and the one i got as a replacement for that was a pvr-802w So i don't know what lens i should get as i should be getting it from the internet and if it will work. Or if i have another option like cleaning the lens i have. Or if the chip is the problem as it read original games why shouldn't backed up ones?.