Question Very strange power supply issues with old and new motherboard ?

[Francis SM]

Hello everyone,

First time posting here, I am very desperate. Been looking for a solution for a while now.

I was given an old ES1-521-48YQ Acer laptop not so long ago. I bought a new SSD and new RAM for it. I have had quite some challenge with it. After a few attempts at installing the SSD and new RAM, I was succesful. The whole rig was functionning perfectly until I was trying to close the laptop, and screw everything back into place. When I pressing, either with tighting the screws or pressing with a finger in the top left corner, the laptop suddenly shut down. I suspected a short circuit. So I openned the laptop again and tried to see where metal could touch metal... unsuccesfully. After a few attemps of trying to solve this, the power just wouldnt come on anymore. Pressing the power button wouldnt start the laptop again. It could've been connection issues, because it happened a few times that the connectors were loose or not proprely connected when I tried to mount everything back together. Let me go on...

At this point, im not getting power whatsoever. I tried unplugging, replugging battery and power supply without succes. I tried reinstalling RAM, reinstalling different RAM sticks. I have trouble shooted the problem. I used a multimeter to diagnoser the power supply. After research, the mobo is getting the expected 19,25V supply on all of its 4 pins, but the orange power light of the MOBO would never come on. At this point, I knew the powersupply, the power jack, the power cables, and the power connectors on the MOBO were all fine. The MOBO seemed the problem since it wasn't able to handle the power properly, since the light wouldn't come on, and the laptop wouldn't power on either with or without the battery attached.

So I bought a new MOBO from Aliexpress. After reinstalling the heatsink and everything on the NEW MOBO, I was expecting my problem to be solved, but even with the new MOBO, I am facing the exact same issue. The laptop doesn't power on, and the powerlight on the MOBO isn't turning on, even when nothing else is plugged into the mobo. I still checked... reading 19,25 V on each of the pins on the MOBO power connectors.

I am wondering, wth am I doing wrong? Did they send me a defective MOBO or did I kill it too? I took measure against electrostatic discharge, so at this point I am quite baffled, and honestly quite shocked and discouraged too. Seems I have tried everything I could.

You guys have any suggestions that might solve the issue? At this point I am considering just starting from scratch. Thank you very in advance.

Francis SM

 

[Ralston18]

Did you test the power button?

Just as a general reference:

https://www.lifewire.com/fix-a-computer-that-shows-no-sign-of-power-2624442

Look for other similar links as well.

(Noted a suggestion that the CMOS battery be replaced with a fresh battery.)

 

[Francis SM]

Thank you for your suggestions @Ralston18. I believe that the battery could indeed be the culprit, but it is difficult to change on those MOBO. I read 2,75 V on the old battery, but only 2,60 V on the newly bought MOBO, which could indicate that the old battery was actually better than the one I bought.

As for the power button, I don't think it is the issue, since it worked proprely not so long ago when everything worked fine. The problem is the MOBO not getting any power at all, that is the real issue here. Thank you for your ideas.

I think the CMOS battery is probably my last resort option, even though it's hard to believe that it is the culprit on 2 different MOBO. It looks relatively hard to change though so maybe I'll take it in for professional repair.

I'm open to new suggestions.

Thanks again.

Francis

 

[Francis SM]

My motherboard is a B5W1E LA-D121P, I could found the schematics for it online here: https://forum.laboneinside.com/viewtopic.php?f=6&t=2778

Seems like I will be unable to remove and replace the CMOS battery with this MOBO. All that is left for my is trying to ''open'' the shortpads on the the mobo (bottom of page 9 in the schematics) to clear the CMOS.