Logic board is boot looping
Hello fellow technicians,
I have chosen to attempt a board level repair on this laptop, this is a first for me since my repairs usually restrains to phones&tablets since they’re smaller and easier IMO to troubleshoot.
The issue here is a boot loop. both the power LED and the charging LED will light up when prompted to boot but the laptop will shut down within 1 second,the fan will also spin for that brief second, I tried booting the laptop with a different CPU, without any CPU, with a different charging cable, with fully charged battery only, with no RAM or CMOS battery and the issue remained the same leading me to conclude the problem is in the circuit itself.
I checked the schematics a bit and realized almost the entire circuit has a 19V power rail going through, so I checked with my multimeter but I am not sure where to begin, where should I start checking first for that 19V power rail? From what it seems to me is there is something bringing the line down as soon as it is prompted to boot and therefore shuts down, I’m not expecting anybody to magically come out with the component at issue here but rather wondering for the people that has had a similar issue in the past where was their problems situated around? Thankyou.