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The PS3 that I have is a launch system so considering how old and how often I use it I'd say I'm very impressed with the build quality. And I thought about just getting a new model but I play my old PS2 and PSX games pretty often so I wanted to keep the old system for it's backwards compatibility.
Last weekend I got the YLOD and after doing some online research I figured out exactly what the issue was. I knew iFixit had to have a guide on how to fix the console but I didn't expect a whole repair kit.
After getting the kit I followed the iFixit guide step by step and didn't run into any issues. It took me a lot longer than the 1 hour repair time they report but I had to clean the PS3 as I went. <sarcasm> Turns out alot of dust accumulates after 5 years of use </sarcasm>
So far the PS3 has been working like a champ. The fan seems like it does not have to work as much and I hope to get alot more use out of it before it gives up the ghost.
One of the biggest things to remember is how a few ribbons and wires run before you remove them. For instance make a special note on how the WiFi/Bluetooth ribbon runs through the motherboard cover.
Other than that, you might want to have some compressed air to help clean.