Disc Read Error on PS2 - laser adjust not working

Hey guys,
I bought a modded ps2 on eBay a few months ago - it was working fine until yesterday and all of a sudden it doesn’t read any discs at all! (including originals and DVDs, just get “disc read error” message). This is really weird as most ps2s stop reading gradually overtime… Any ideas why this could be happening or how to fix it? I have opened it up and adjusted the laser height but that hasn’t done anything, perhaps it needs a new one or the mod chip has broke (its a magic 3.1)?
Any advice would be great guys!
Dawson