Why did the motherboard lose power after cleaning the PSU?

Question

Computers

Hello.

On the board, after cleaning the PSU, the red LED does not light up, which symbolizes the state of electricity on the board. After several hours of picking the board and power supply, I did not find any downed elements, and, in principle, I cleaned the whole thing with a carefully soft brush.
In the past, PC cleaning was limited to blowing out coolers and cases. I didn't touch the power wires. After getting into my hands with a PC, everything remained the same.
I refer, perhaps, to a bad contact somewhere, if I didn’t dream that the LED was on for a moment for a couple of seconds after this very cleaning.
Your suggestions?

Answer 1

Perhaps you can check the output power supply with probes, but I'm not an electrician.

The simplest check is to start the PSU using the folk method with a paperclip: https://www.google.com/search?q=PSU+paperclip
If the PSU fails to start with a paperclip, then the problem is in the PSU.

Answer 2

I hope the PC was completely de-energized before cleaning?
Thoroughly blow through the power contacts on the power supply and the motherboard ...
Well, just in case - check with another power supply ... maybe a short one caught somewhere