Sorry. Should have been more descriptive.
The fat PS3 used a chip capacitor that is labeled as NEC TOKIN, and they look like this.
It has been discovered that they have a very high failure rate, and the yellow light of death on fat PS3's was caused by them going bad. However, for many years people thought the fix for the YLOD was to try to reflow the solder balls under the CPU and GPU, or for repair companies to completely remove the CPU/GPU and resolder them. It appeared to work, because when heated the token caps temporarily regain proper functions, but it was never a permanent solution, not to mention it was far more risky.
The current fix is to replace the Tokin capacitors with more reliable capacitors. So you'd end up with something like this.
The reason I mention them is because last I checked there were still many places claiming to do PS3 repair that don't replace those capacitors, and instead use outdated information and do the much more difficult job of resoldering the CPU/GPU.
Basically it's a good test to see if the repair place you choose has kept up to date on their info. It sounds like you might just need a good cleaning and new thermal paste, but better to go with a place that knows their stuff rather than one using years old info.