Samsung np270e5u no display issue

[ashan000]

I have np270e5u laptop with no display issue. no vcore voltages presents. other voltages are ok i think. (i am new to this field). the cpu fan spinning. i found a smd is getting hot a bit. problem is, i can't identify that component exactly(a mosfet(6pin) or another kind of smd). and also a cap and a resister connected to pin3 not show any value.

i will add images to understand easy.







can someone help me to clear this out..?
sorry for my bad English..

[ashan000]

Re: Samsung np270e5u no display issue

https://drive.google.com/file/d/1OJq...ew?usp=sharing

https://drive.google.com/file/d/1utm...ew?usp=sharing

[mon2]

Re: Samsung np270e5u no display issue

Hi. Can you post a larger pic of the logic board ? Unable to find this in my database.

Do link any schematics / bv files if available on this forum.

The package of the referenced part is SOT23-6.

[ashan000]

Re: Samsung np270e5u no display issue

i searched google. but, I couldn't find any schematic or board view for this..
here is the full board.

[ashan000]

Re: Samsung np270e5u no display issue

Hi. Can you post a larger pic of the logic board ? Unable to find this in my database.

Do link any schematics / bv files if available on this forum.

The package of the referenced part is SOT23-6.

thank u for this reply..

[mon2]

Re: Samsung np270e5u no display issue

Bingo!! @SMDFlea - need that washer & dryer prize Even LG is ok.

Found it = Q508. Your last batch of pix helped.

Q508 = AO6409L,P,-20V,-5000mA,45mohm. Datasheet is attached.

BV & partial schematic files are attached.

[ashan000]

Re: Samsung np270e5u no display issue

Bingo!! @SMDFlea - need that washer & dryer prize Even LG is ok.

Found it = Q508. Your last batch of pix helped.

Q508 = AO6409L,P,-20V,-5000mA,45mohm. Datasheet is attached.

BV & partial schematic files are attached.

you are a genius.. thank you. i will look it further..

[ashan000]

Re: Samsung np270e5u no display issue

Bingo!! @SMDFlea - need that washer & dryer prize Even LG is ok.

Found it = Q508. Your last batch of pix helped.

Q508 = AO6409L,P,-20V,-5000mA,45mohm. Datasheet is attached.

BV & partial schematic files are attached.

bv files ware very useful. thanks again..

So i checked. p3.3v was missing according to board view(q508 pin 1,2,5,6).
then i found a shorted cap (part no 100 p3.3v ). i replaced it. now vcore voltages are presents.

but now the pins show(q508 pin 1,2,,5,6) 2.4v only.

and no voltage in L9 coil.. i gues it is gfx core voltage.
and not spinning fan now.
also pch and cpu heats.

any suggestions.??

[mon2]

Re: Samsung np270e5u no display issue

Gfx voltage will enable with a heavy graphics load, according to other forum posts. So ignore this rail for now.

Remove all power. Measure the resistance to ground of each pin of the above mosfet. Post the readings.

Has this mosfet been replaced? (Q508)

Do you have this area of the logic board with ~3v3 ? If not, some part is sinking too much current and causing this rail to lower to ~2v4. The nearby caps are suspects.

[mon2]

Re: Samsung np270e5u no display issue

Also check the voltage @ L1 inductor. What is the reading ?

This is where the 3v3 starts that is then switched by the mosfet referenced in this thread.

Is the voltage @ 3v3 or is it lower ?

[ashan000]

Re: Samsung np270e5u no display issue

Also check the voltage @ L1 inductor. What is the reading ?

This is where the 3v3 starts that is then switched by the mosfet referenced in this thread.

Is the voltage @ 3v3 or is it lower ?

voltage @ L1 3.3_aux presents. 4th pin of q508 have 3.3_aux.. as u say. i should try replacing the mosfet. but still i couldn't find a mosfet to replace. as soon as i replace, i will reply with result.

if u have schematic pdf file, can you send to me..?

[ashan000]

Re: Samsung np270e5u no display issue

Gfx voltage will enable with a heavy graphics load, according to other forum posts. So ignore this rail for now.

Remove all power. Measure the resistance to ground of each pin of the above mosfet. Post the readings.

Has this mosfet been replaced? (Q508)

Do you have this area of the logic board with ~3v3 ? If not, some part is sinking too much current and causing this rail to lower to ~2v4. The nearby caps are suspects.

if i inject voltage q508 p3.3v rail.. what it would be? is it a bad idea?