Which one is dead, the CPU or the motherboard?
Which one is dead, the CPU or the motherboard?
Have you removed the PSU from the case and attempted a jump start, checking if the PSU fan starts rotating?
If you use the 20+4 pin connector on the PSU and position the clip on the right side, inserting a paperclip into the second and fourth wires on the right side can help initiate the start. If the fan begins to spin, it suggests the PSU is operational. If it doesn’t move, the PSU may be dead.
If the fan does spin, consider using a multimeter to verify voltages at the connectors. The following links provide guidance on expected voltage levels:
https://www.google.com/search?q=24+pin+p...OQx31YM%3A
https://www.google.com/search?q=24+pin+p...lex+pinout
https://www.google.com/search?q=24+pin+p...wer+pinout
Update: Ensure the PSU is fully disconnected from the computer before proceeding. Also, avoid letting the paperclip contact any metal parts inside the connector (like a cardboard box). Never touch the power supply casing while handling the paperclip; you’ll experience a mild shock but not serious harm.
Disconnect the coin cell and consult the motherboard manual; these methods ensure safety.
Just because LEDs turn on doesn't guarantee they're receiving the right voltage. I've seen power supplies output 8V on 12V connectors and the LEDs still worked.
The paperclip method can be risky? Jump-starting a power supply is covered in CompTIA A+ training—it's simple as long as you avoid touching an active ground while handling the paperclip. I wouldn't consider it more dangerous than not unplugging a system before connecting its power connectors (which everyone does).