hp 450 g8 not turn on(DAX8QMB28A0 REV:A)

[arber1232]

Hi everyone !!!
I have a Hp 450 g8 in the service which does not turn on. There is no light when I put the charger, I tried several chargers such as blue head and type-c but again no light.
I have 19v in the mosfet and 3.3v in the power button. In the legs of the bios I have 0.1v and in the nuvoton ic I have 0.1v, so I still don't have a schematic for this laptop. I have checked all the coils in ohms but do not have shorts
can i help me ?

[mon2]

Re: hp 450 g8 not turn on(DAX8QMB28A0 REV:A)

Which charger IC is onboard? Review the usual DCin mosfets and the charger IC should be nearby.

[arber1232]

Re: hp 450 g8 not turn on(DAX8QMB28A0 REV:A)

Bq24780s

[arber1232]

Re: hp 450 g8 not turn on(DAX8QMB28A0 REV:A)

Acn=0v
acp=19.5v
csmrc=19.5v
acdrv-25v
acok-0.1v
acdet-3,3v
adp-0v
VCC=18.9V
LODRV=0V
REGN=6V

[mon2]

Re: hp 450 g8 not turn on(DAX8QMB28A0 REV:A)

ACP is ok but ACN is not. Double check the voltage to ground of ACN.

There will be a current sense resistor of a few milli-ohm between ACN and ACP so it does not make sense that one side will have 19v but the other side will be 0 volts. At least on a known good board, both legs should be ~19v.

Also, remove all power, meter in resistance mode. Check the resistance to ground of ACN.

[mcplslg123]

Re: hp 450 g8 not turn on(DAX8QMB28A0 REV:A)

ACN/ACOK/ACDET-all are wrong. Re check your measurements.