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Old 10-29-2020, 04:24 AM   #1
stingerchamp
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Post HP OMEN AX236TX DAG35DMBAD0 rev:D NO power no light

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 ,
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Old 10-29-2020, 08:16 AM   #2
mcplslg123
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Default Re: HP OMEN AX236TX DAG35DMBAD0 rev:D 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.
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Old 10-29-2020, 09:11 AM   #3
stingerchamp
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Default Re: HP OMEN AX236TX DAG35DMBAD0 rev:D NO power no light

Quote:
Originally Posted by mcplslg123 View Post
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.
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Old 10-29-2020, 11:25 AM   #4
SMDFlea
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Default Re: HP OMEN AX236TX DAG35DMBAD0 rev:D NO power no light

Quote:
Originally Posted by stingerchamp View Post
Thanks for the input but this PNP Bjt dual array is there for some reason.
PQ1004 datasheet - https://www.diodes.com/assets/Datasheets/ds30109.pdf

One area that you can study with a P channel mosfet is the Gate Threshold Voltage ,which can be very misleading. http://www.aosmd.com/pdfs/datasheet/AON7403.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 =

Last edited by SMDFlea; 10-29-2020 at 11:56 AM..
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Old 10-30-2020, 12:14 AM   #5
stingerchamp
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Default Re: HP OMEN AX236TX DAG35DMBAD0 rev:D NO power no light

Quote:
Originally Posted by SMDFlea View Post
PQ1004 datasheet - https://www.diodes.com/assets/Datasheets/ds30109.pdf

One area that you can study with a P channel mosfet is the Gate Threshold Voltage ,which can be very misleading. http://www.aosmd.com/pdfs/datasheet/AON7403.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

Last edited by stingerchamp; 10-30-2020 at 12:25 AM..
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Old 11-01-2020, 08:18 AM   #6
stingerchamp
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Default Re: HP OMEN AX236TX DAG35DMBAD0 rev:D NO power no light

hello
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Old 11-02-2020, 08:57 AM   #7
stingerchamp
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Question Re: HP OMEN AX236TX DAG35DMBAD0 rev:D NO power no light

Quote:
Originally Posted by SMDFlea View Post
PQ1004 datasheet - https://www.diodes.com/assets/Datasheets/ds30109.pdf

One area that you can study with a P channel mosfet is the Gate Threshold Voltage ,which can be very misleading. http://www.aosmd.com/pdfs/datasheet/AON7403.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.
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