Acer V Nitro VN7-792G won't power on after liquid spill. Battery or MB issue ?

Hi,

yesterday I unfortunately spilled half a glass of beer (not a so good idea to have a drink visio party during the lockdown 😁) on my laptop keyboard/touchpad (an Aspire V Nitro VN7-792G).

I immediately unplugged the power cable and flipped the laptop over so as to prevent liquid from invading the whole enclosure. I forgot to power it off and after 2 minutes, it shutdown itself.

Once shut down and wiped I opened the case, removed the keyboard and the battery to check the internal damages. No moisture on the motherboard, no burnt smell (rather a beer smell). Good news ! I did a cleanup with a slightly moist cloth so as to remove the remains of beer and remove the dust and put everything back this morning.

But my laptop won't power on anymore and I'd like to understand why (and fix it if it can be fixed).
So far the symptoms are:
* battery is charging (at least the amber/blue charging LED seems operational: no blink, no flash... went from amber to blue during a charging session)
* the power on button on the keyboard does absolutely nothing
* I have tried the battery reset procedure (pin hole press on the back of the laptop) with no success,
* I have tried the power switch on the motherboard with no apparent effect,

Is there any way of measuring the battery output voltage with a multimeter so as to check whether the problem come from the power source of from another component ?

Thanks in advance for your answer,

Regards

Accepted answers

All comments

BalkanBoy

Hi,

if you're lucky you got dodgy keyboard now, maybe it's preventing laptop from powering on, maybe power switch is faulty, it's part of a keyboard on that model. Battery got nothing to do with it, you can power on every laptop without battery.

What do you mean when you say you tried with internal power switch?

I've never saw laptop with internal power switch, I guess you were pressing internal reset button (where needle from pinhole goes).
Some laptops got solder joints for internal button but button itself is never soldered, you got to use tweezers or something. If you find one of those you should have 3.3V on it and you should short them to ground to power on laptop. If you're not sure what you're doing it would be better to take it to repair shop because motherboard could really be working and you're risking burning it.

Regards

Celeph

Hi @BalkanBoy ,

thanks for your answer. Actually I don't think I will burn the MB (or at least I am willing to take the risk), I have some practice in mounting or disassembling my PCs but I have never had to deal with a smart battery and I do not know if I can test the battery voltage 'as is' or if it need to be sent a command via the bus in order to start powering the board.

My main concern is to tell whether the battery or the board (or both

) is dead. Because of the lock it can not bring the computer to a repair shop but I can still order spare parts...

For the power button, according to this video (6:17 and after... this is not exactly the same model but mine looks very similar) there should be a power button (

https://youtu.be/tRvgGJuyQq4?t=377).

There are two buttons on my config. The first one is indeed the battery reset:

Image: https://us.v-cdn.net/6029997/uploads/editor/ub/qdx2c3wlxjrm.jpg

and I thought the second one was for powering the MB:

Image: https://us.v-cdn.net/6029997/uploads/editor/q6/yjcmu0gmfrd4.jpg

BalkanBoy

I don't believe that's power button, could be battery switch, some Acers got that protection. Try pressing motherboard against palmrest and see if it "clicks", I think that switch got to be closed all the time. You can try to power it on on keyboard connector with tweezers, should be pin 27 and 28, take a look at photo. While you doing it please make sure that switch on 2nd photo is pressed too.

Image: https://us.v-cdn.net/6029997/uploads/editor/bk/hnmpz4jutd1h.jpg

Try to power on board only, remove everything else including battery. (leave heatsink and fans only)
If it doesn't power on check if you got 3.3V between GND and pin 27. Put GND on copper circle anywhere on motherboard, it's much easier.
Report please.

Celeph

Ok, thanks again !

You were right the button is a battery protection switch. When it is not pressed, the battery does not deliver any power, when it is, I get 12V at the battery output.

Regarding the keyboard connector, I am not quite sure about the procedure you've suggested while the battery is removed (0V everywhere) so I have checked with the battery plugged and nothing else.

The results are (my multimeter is not the best of breed)::
GND and PIN28 = 0V l)
GND and PIN27 = 2,5V
GND and PIN26-PIN09 = 0V
GND and PIN08-PIN01 = 3,25V

Good news (?), the fan started when powering the board with a contact between PIN27 and 26.

BalkanBoy

So have you made it? Have you connected display and see if it posts?

Celeph

Hi @BalkanBoy,

actually I was waiting for your feedback...

but yeah I did it.

I got the windows login screen so I guess the MB is OK. Still no success with the keyboard. I may have an issue with the connector or the cable.

I will try and report. Is there any way to test the keyboard in a standalone mode in case it won't work ?

Thanks again and best regards,

Celeph

bad luck... I have put all the pieces together. I can boot and get to windows with my 'paperclip switch' (variant of the tweezers switch 😁) but can't power on the laptop with the keyboard button.

Celeph

Update for the record.
I have 0,2 kΩ internal resistance between pin 28 and 27 on the keyboard ribbon when the power button is pressed so I guess the keyboard is fine.

BalkanBoy

Sorry buddy, I was bit busy. You need new keyboard and everything will be ok. That one is faulty and it's preventing laptop from booting.
Not sure if you can swap it easily or you'll have to buy complete new palmrest. Lot of those keyboards doesn't use screws but plastic seals which are pain in the **** to remove and you have to melt plastics again when you install new keyboard.
Let me know when you do it, until then you can try to isolate every pin on keyboard ribbon except pins 27 and 28 with some thin tape so you can use power button normally and attach USB keyboard.

Regards

Celeph

Hi @BalkanBoy,

Thanks again for your answer, I hope you're well. Actually after a lot of tests I reached the same conclusion... I even tried to plug the keyboard while the laptop was running: instant shutdown effect!

I will buy a new keyboard and the palmrest. Even if it's more expensive I do not have the equipment (and the time) to manage plastic seals removing and soldering.

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