Hello,
I am diagnosing my daughters laptop motherboard, its HP(8th Gen i5, dGPU) laptop with G35N motherboard, it turns on for a second and then off(without fan spinning). I found some loose screw inside(display hinge stuck), pointing to possible short caused by it, so far I tracked fault on +3V and +1.2V, I have fixed 3V issue by replacing TPS22976DPUT, but found faulty 1.2 just recently and I wanted to try out injecting it externally, to see if it comes to life.... me being impatient I tried to inject 1.2V(2A limited) from my dodgy power supply with my voltage probe hooked up and I noticed volage jump up to 1.8V, then I immediately disconnected the power supply... it was connected for about second or less. This line is connected to CPU and RAM, I am not sure how much for how long can kill CPU (replacing RAM is no problem).
Ultimately I found that 1.2 MOSFET(AON7408) has GATE to PHASE short... so I am wondering if I should order the mosfet or if you think that CPU is dead.
The IC(APW8868B) that creates 1.2 should provide also initial signal for HWPG based on its PGOOD out, which of caused do not appear as the mosfet is shot.
Thank you for any suggestion
I am diagnosing my daughters laptop motherboard, its HP(8th Gen i5, dGPU) laptop with G35N motherboard, it turns on for a second and then off(without fan spinning). I found some loose screw inside(display hinge stuck), pointing to possible short caused by it, so far I tracked fault on +3V and +1.2V, I have fixed 3V issue by replacing TPS22976DPUT, but found faulty 1.2 just recently and I wanted to try out injecting it externally, to see if it comes to life.... me being impatient I tried to inject 1.2V(2A limited) from my dodgy power supply with my voltage probe hooked up and I noticed volage jump up to 1.8V, then I immediately disconnected the power supply... it was connected for about second or less. This line is connected to CPU and RAM, I am not sure how much for how long can kill CPU (replacing RAM is no problem).
Ultimately I found that 1.2 MOSFET(AON7408) has GATE to PHASE short... so I am wondering if I should order the mosfet or if you think that CPU is dead.
The IC(APW8868B) that creates 1.2 should provide also initial signal for HWPG based on its PGOOD out, which of caused do not appear as the mosfet is shot.
Thank you for any suggestion