@Sylver said in monitor turns off when connecting to cpu:
@nightcode1 okay, I just saw in the first photo you attached that it does have a speaker integrated into the board (in this case named BUZ, from buzzer).
If removing absolutely all components except processor and power supply doesn't emit any beep, it's possible that there is some internal damage to the board that is very difficult to identify, as we have no way to guide ourselves...You can also see a swollen capacitor in the first photo. It doesn't have to be the cause of the problem, but if it has been like this for a long time, it's evident that it hasn't filtered the current at the point where it was planned to do so and it may have damaged the internal component it served.
With no response from the board, everything points to there being some internal damage.
What happened when you didn't connect the P4 and tried to boot was that the board didn't detect the power supply for the CPU and the reaction is usually like that, fan at maximum and doesn't turn on.
If by any chance the board's buzzer didn't work (it's rare), you could try mounting a PCI-express graphics card directly and see if there was any luck, but everything points to the board being damaged internally as I told you.
Regards
hello friend, in effect I disconnected everything and only left the P4, P20 speaker connected and nothing that emits beeps, the power supply turns on but no beeps 
I don't have a tester so I'll have to send it for review to at least know what it has
