Acer model N15W4 - does not start

[Jane]

When I connect mainboard to my laboratory power supply ( without pushing ON /OFF button) it takes about 10mA for about 5 seconds. Then current drops to 0A.
I can push ON/OFF button and fan starts ,also a LED - mark PLED1- shines in blue, current is about 0.214A.
But when I connect LCD there is no image.

Can you please give me a clue where to search a fault?
Thank you

[mon2]

Re: Acer model N15W4 - does not start

1) Post or link a schematic / boardview files if available on this forum.

2) review the adapter voltage at the DC in connector - voltage reading ?

3) locate in this area will be the usual 2 x DCIN mosfets.

a) post the markings on the mosfets so we can find their datasheets

b) also near this area will be the charger IC - what are the markings on the charger IC ? (so we can find the datasheet for a review)

c) Remove all power -> meter in resistance mode -> check the resistance across each of these DCIN mosfets.

source & drain
source & gate
gate & drain

post the resistance values and also the scale used on your meter.

We are checking for shorted / defective mosfets which will have low resistance readings. Be sure to remove all power and no battery on the logic board when performing resistance checks.

[mcplslg123]

Re: Acer model N15W4 - does not start

Give the mb silkscreen number. What are the rails which are coming up and not coming up after pressing power button? You can measure them on coils to begin with.

[Jane]

Re: Acer model N15W4 - does not start

Thank you for your reply.
I was not sure which mb number you wanted so I am posting pictures of mainboards from top and bottom.
And which rails and where should I measure?
There are some voltages because I can start the laptop, fan works for a few seconds and also a LED - marked PLED1- shines in blue, current is about 0.214A.
But no picture on LCD at all