Had a slim PS3 today that showed no signs of life,as though the PSU was faulty. Further investigation allowed me to test the PSU and it was ok. I noticed that the 5v rail dropped dramatically when the standby power was switched on. I was able to track a short on the wifi/BT module even though there was not a general 5v rail short.

I went ahead and replace the module with one I harvested from a faulty board

After replacing the WiFi/BT module I was greeted with a red standby LED on the console and it then booted fine.

Another successful diagnostics and repair 🙂