I made some measurements in the affected area of the laptop boot. On the wire connector that goes to the power button module, I have the required 3v valw on pin 7 (3.4v). While on pin 8 (pwrsw) I have 7.2v. When I press the start button, the PWR LED lights up (I analyzed the signal, in fact while it is pressed the voltage goes to zero and then returns to 7.2), but the fan doesn't start and nothing else. So pressing the start button correctly reaches the motherboard on pin 8 of the cn44; I also tried starting by short-circuiting J1, and ok the pwr led starts.

I then measured in the...

Hi, I have an old Sony vaio VGN-FE laptop, it has always worked well, the other day I turned it on and I have the green light on, but nothing starts (the fan stays still, it doesn't even try to start) . I have no experience in the field of PC card, but I have all the necessary equipment for electronic repairs. For now I have only dismantled the motherboard and saw that the 19.5Dc input is there. Any help in finding out what went wrong?

Add two photos of the motherboard; I don't know how to attach the service manual, but it's easy to find online (Sony Vaio mbx149)​
Thank you...