HP OMEN AX236TX DAG35DMBAD0 rev:D NO power no light

[stingerchamp]

HP OMEN AX236TX DAG35DMBAD0 rev NO power no light.


Hi ,

This is another laptop with same problem in which there is no Power to the system while when checked for first two mosfet switching (19v rail area).

I am getting 18.2 volts at the gate of first mosfet PQ1002 and it is a P-channel mosfet.

PQ1002 first mosfet:

pins 1,2,3=19volts , pin4=18.2 volts , pin5,6,7,8=19volts

PQ1002 gate is controlled by PQ1004 voltage divider circuit , if we calculate for voltage at gate of PQ1002 it should be around 15volts (due resistors 220K,1M) but i am getting 18 volts.


PQ1003 second mosfet:


pin 1 ,2 ,3=0 volts , pin 4= 0 ,

[mcplslg123]

Re: HP OMEN AX236TX DAG35DMBAD0 rev NO power no light

PQ1002 gate voltage is correct. 1M & 220K are not voltage divider circuit. Read the schematic carefully and try to understand it. You are not getting any voltage on PQ1003 pin 1,2,3 and thats your +PRWSRC-means 19V rail. What is the impedance on pin 1-2-3 of PQ1003?? Its likely to be shorted to gnd.

[stingerchamp]

Re: HP OMEN AX236TX DAG35DMBAD0 rev NO power no light

PQ1002 gate voltage is correct. 1M & 220K are not voltage divider circuit. Read the schematic carefully and try to understand it. You are not getting any voltage on PQ1003 pin 1,2,3 and thats your +PRWSRC-means 19V rail. What is the impedance on pin 1-2-3 of PQ1003?? Its likely to be shorted to gnd.

Thanks for the input but this PNP Bjt dual array is there for some reason.

[SMDFlea]

Re: HP OMEN AX236TX DAG35DMBAD0 rev NO power no light

Thanks for the input but this PNP Bjt dual array is there for some reason.

PQ1004 datasheet - https://cdn.badcaps-static.com/pdfs/...6fb3e5c604.pdf

One area that you can study with a P channel mosfet is the Gate Threshold Voltage ,which can be very misleading. https://cdn.badcaps-static.com/pdfs/...c59cbfa3b0.pdf
With no power attached chek PQ1002 in Ohms ,

red lead on drain,black lead on source. Ohms =

Black lead on source,red lead on drain. Ohms =

[stingerchamp]

Re: HP OMEN AX236TX DAG35DMBAD0 rev NO power no light

PQ1004 datasheet - https://cdn.badcaps-static.com/pdfs/...6fb3e5c604.pdf

One area that you can study with a P channel mosfet is the Gate Threshold Voltage ,which can be very misleading. https://cdn.badcaps-static.com/pdfs/...c59cbfa3b0.pdf
With no power attached chek PQ1002 in Ohms ,

PQ1002

with only cmos cell

red lead on drain,black lead on source. Ohms = display OL

Black lead on source,red lead on drain. Ohms = display OL

PQ1003

red lead on drain,black lead on source. Ohms = 2.2
Black lead on source,red lead on drain. Ohms = 2.2

red on pin5 and black on pin4 gate = 195 for 1 sec than reaches L

[stingerchamp]

Re: HP OMEN AX236TX DAG35DMBAD0 rev NO power no light

hello

[stingerchamp]

Re: HP OMEN AX236TX DAG35DMBAD0 rev NO power no light

PQ1004 datasheet - https://cdn.badcaps-static.com/pdfs/...6fb3e5c604.pdf

One area that you can study with a P channel mosfet is the Gate Threshold Voltage ,which can be very misleading. https://cdn.badcaps-static.com/pdfs/...c59cbfa3b0.pdf
With no power attached chek PQ1002 in Ohms ,

red lead on drain,black lead on source. Ohms =

Black lead on source,red lead on drain. Ohms =

Hi,
In view of your private message , I have to change the multi meter because this one is a cheap one DMM and i can not perform Diode mode test(not supported) with this clamp multi-meter Dt-266 , I do not want to pull out anything from motherboard and have a desire to test the components while they are still in motherboard without any power attached. suggest any good DMM if any.

[stingerchamp]

Re: HP OMEN AX236TX DAG35DMBAD0 rev NO power no light

Just to complete this thread

I successfully repaired my laptop ,vccsa coil was having liquid damage via hp omen SD card slot as it is very close, two caps were shorted and vccsa is attached to CPU therefore I was not getting signal.

Replaced two caps and pq4012 problem solved
Thanks all