After almost exactly three years of loyal servitude, my PS3 up and stopped reading Blu-ray discs recently. DVDs and CDs still read perfectly fine, despite the content (movies, music, games, etc.) but nothing off a BD would register a blip on the system's awareness, by and large.
Every now and then it would tell me what disc was in, I'd try to load it up, the system would choke, barf error codes at me, and collapse in on itself back to the Home screen or reboot entirely. None of these outcomes are optimal.
So what's an enterprising lad to do with a $500 console that's 24 full moons outside of warranty? Well, I priced getting it fixed, easily $150 and up for Sony to probably just send me a refurb unit and lose all my save data (well, only those irritating-as-hell files that are read-only and can't be manually backed up, and you can't restore HDD backup data to a different system), or around $100 for someone at a local shop to do it for me. Having cracked the case on every other box in the PlayStation console family for vaguely similar issues, I figured it was worth poking around inside. It's not like I was invalidating my warranty or anything.
If you're in a similar situation and want to replace your laser — something that any evolved chimp with a half hour to kill could do, myself included — there are two critical bits of info you need to gather:
1. Do you have a cyclops PS3? More recent PS3s have two lenses in the housing, one that is just for BDs and another that reads DVDs and CDs to cut down on wear on either one. However, launch units (everything up to the redesigned 80GB with only two USB ports, I believe) only have a single lens, which is more prone to wear out faster. Single lens model number is KES-400, and the dual lens is KES-410. Both are generally available on Amazon or eBay for around $75 including shipping.