My laptop not charging and not power on

[SuperAlain]

Hi all,

I have a problem with my laptop it doesn't turn on and it doesn't charge.

When I plug the adapter, the laptop start and stops quickly.

I removed the motherboard to try power on the laptop directly through the 2 pins, when I pass the screwdriver on the two pins the LED lights up orange and it goes off.

I tested the mofsets with my multimeter and I got these measurements :





I'm really lost 

Any ideas ? thank you so much!

[Mr. Scram]

Very comprehensive images. Nicely done. When you say the laptop starts and stops quickly, what you do mean exactly?

[Jwillis]

I would start at the battery pack first as the most plausible problem.   
Many times when charging or power issues pop up for lap tops it turns out to be the battery pack. These packs have safety features built in that prevent charging when they fall outside of specific parameters. Even if one battery is out of specification yet the others are fine . This can also prevent the lap top from running off the AC/DC power supply.

[Renate]

Is the big connector with two red, two black the power jack connector?
Where's the battery? Have you checked if there is any voltage on it.
Have you tried with no battery attached?
Do you know whether this laptop works with no battery?

I had a problem with an Android tablet that was dead, dead, dead even plugged in.
The battery was showing zero volts.
I jumpered in a 1K to the battery and that was enough to get the charger logic to boot.,

[Buriedcode]

Whats the model of the laptop?  Although they aren't always freely available, you'd be surprised how many laptop schematics and perhaps service manuals are on the web.

Power is always controlled, so it might not be a problem with the power components, but rather startup failure preventing the charging.

We really need a lot more info

[SuperAlain]

Hi! Thank you very much for your answers

So

Very comprehensive images. Nicely done. When you say the laptop starts and stops quickly, what you do mean exactly?

Thank you my friend I meant that my laptop starts a few seconds and shuttdown quickly, the CPU fan also stops. It happens only when I plugged-in and unplugged the power supply adapter but if I try to start the laptop directly through the button nothing happens.

I would start at the battery pack first as the most plausible problem.   
Many times when charging or power issues pop up for lap tops it turns out to be the battery pack. These packs have safety features built in that prevent charging when they fall outside of specific parameters. Even if one battery is out of specification yet the others are fine . This can also prevent the lap top from running off the AC/DC power supply.

I removed the battery, same problem my laptop does not work :/

Is the big connector with two red, two black the power jack connector?
Where's the battery? Have you checked if there is any voltage on it.
Have you tried with no battery attached?
Do you know whether this laptop works with no battery?

I had a problem with an Android tablet that was dead, dead, dead even plugged in.
The battery was showing zero volts.
I jumpered in a 1K to the battery and that was enough to get the charger logic to boot.,

1 - This cable give the 19v from the power supply adpater to the motherboard, I tested and I have 19 volts on the two red wires

2 - The battery is charging but the laptop is not power on with the battery

3 - Yes I tried, same problem, when I plugged-in the power supply adapter,  the laptop run a few seconds (I can hear the CPU fan also) but it stop runing quickly.

4 - I tried without battery but is not working

Whats the model of the laptop? 

Acer extensa 7620z 17 inch model

[SuperAlain]

It's normal that I have 6v instead of 19v on the u40 mofset ?

Thanks and thanks again!

[Manul]

"The battery is charging but the laptop is not power on with the battery"

So is it charging or not?

Are you sure it is electrical problem? I once fixed a laptop for a friend, it was similar symptoms, turn on for a few seconds and shutdown, nothing on the screen. I removed a bios chip, flashed it and it was fixed.

How much current does it take for these few seconds while it is on? How about standard power rails, like DRAM (1.8V ?), CPU core, 3.3V, etc., do they apear for a short time?

[Buriedcode]

...I once fixed a laptop for a friend, it was similar symptoms, turn on for a few seconds and shutdown, nothing on the screen. I removed a bios chip, flashed it and it was fixed...

I don't think bios chips have been socketed for a couple of decades, especially not on laptops.

I think I found the schematic, but rather than link to a less-than-reputable site, I downloaded it and attached it here.   The website might be fine, but I don't like providing urls to sites with popups.
I also found a service manual, the last ~ 70 pages of which seem to show trouble shooting methods, and possible error codes (beeps, indicator flashing etc..) but its too big to upload

So here's the link: https://www.manualslib.com/download/232618/Acer-Extensa-7620.html

[Manul]

I don't think bios chips have been socketed for a couple of decades, especially not on laptops.

And why non socketed is a problem?  It was a laptop from around 2017, it had bios on SO-8 SPI flash (4MBit if i remember).

[SuperAlain]

Hello, I don't know, I'm really lost with this laptop

Yes the battery is charging and when I want to turn on my laptop just with the battery it won't turn on.

It only turning on when I remove the battery and plug only the adapter... It just turn on for a few seconds and it turns off   

I forgot to say it, the computer turns on for a few seconds only when I remove the Cmos battery and I connect the power supply adapter .... With the cmos battery it doesnt turn on ...
It's really crazy!

Is there a possibility of a shorts on the motherboard?

Thank you