The Sony Playstation 3 Fat, the first version Sony build, suffers for the well know problem of the Yellow Led Of Death (YLOD), that cause the PS3 not to boot.
It happens that I've found a PS3 Fat in the dumpster. It works for a while, than It turns off due to thermal overload.
First thing I've try, was to reflow the two main processing unit.
I take my hot air soldering station, set it to 200 Celsius degree and move for 2 minutes on the first then on the second unit. I keep moving around while reflowing. Second step was done at 250 Celsius degree and 2 minutes.
After the reflow, I've changed the thermal paste, and the PS3 has started working again.
I'm not a big player, so I'ven't use the console for a while. After a couple of month I wanted to play again, but the PS3 does not boot anymore. This time it suffers of the YLOD, it try to boot, then after 1 ore 2 seconds the red led flashes three times and PS3 won't start.
Searching on the web I've found this may due to the NEC/TOKIN capacitors used by Sony in this console version. There are 8, 4 on one side, 4 on the others. They suffer for thermal overload, and eventually loose their capacity.
The fix this time was to remove those caps, and replace with new ones. You can even replace just a couple of those caps, so I decide to replace 4 caps, the bottom side one.
I've used 470uF Tantalum capacitors, model 2R5TPE470M9. 4 for each of the NEC/TOKIN removed.
The difficult part here is to remove the old caps, I've try with air flow solder, without luck, finally I was able to remove those with some brutal force and a chisel. You have to pay attention removing caps cause you may damage your PS3 PCB, and it can be your Game Over.
Anyway, once caps have been removed, you have to clean the PCB trace. There's a big gound plane, so you have to use a solder with some energy. I've used a 100W solder with a big tip (1cm) with a strong thermal mass.
Even to solder the new caps, you have to use a solder with a pretty big thermal mass. I've try with my KSGER T12 soldering station, but even at 450 Celsius degree it was difficult to solder the caps. So I've used a 60W solder with a 3mm tip, the 100W I've used before has a really big tip.
Remember to select low profile caps and solder them next to the PCB, try to stay low, cause once you assembly the console again, just over your caps there will be the mouting shield.
Here you can find a really good guide: https://www.psx-place.com/threads/research-experimental-nec-tokin-capacitors-replacement-ylod.25260/
Once I've replaced the caps, my PS3 has started working. Again I'm not a big gamer, It was more about reparing this console than playing on it... but it has been in the same fashing funny.