Unfortunately if it's already failed that many times your best option is to keep it for parts and get a new one.
This is too true. I didn't perform any maintenance on my unit until it started to overheat and have issues. My PS3 worked until about a year ago so I had many good years from it. It first started when I began playing games in 3D. I had just picked up a 3D tv and glasses and wanted to check it out.
I was able to apply new thermal paste and everything, but have continued to have failures ever since the first full shutdown. I sometimes can get a few months and other times a week. I gave up and ended up buying a new PS3. Good luck to anyone that can reverse an ailing system. To anyone else still rocking one of these backwards compatible beasts I say do some preemptive maintenance now.