Laptop runs on battery but not AC and unable to charge battery.

[YSFang]

Hi.
I have a Toshiba Portege R930.
I am unable to charge the battery and there is no power indicator when I plug in the AC adapter.
The laptop was able to run on battery until its very last drop of juice because I am unable to charge it.
There is no power indicator on the laptop showing the AC adapter is plugged in.
Before this, it was showing signs that sometimes it works sometimes it doesnt. I just tried nudging the jack in any direction thinking it was a connection problem. When it works, not sure was it the nudging that made it work. But now it's totally not working anymore.

Things I have tried.
1. Using a Digital Multimeter, I first measured the adapter output and it was showing the correct voltage in the range of -19V+. Specifically, I plugged in the AC adapter to a power socket and measured for a period of time, and it runs between 18.88v to 19.41V, i assume it's due to AC supply fluctuation, but most of the time it's showing 19.01V. So with this, I assumed the adapter is in good shape. (Adapter rating is 19V, 3.42A).

2. I measured the battery pins from the laptop when the adapter is plugged in and the voltage reads between 0.36V - 0.46V. Not sure is this the correct reading it supposed to output.

3. I then opened up the back casing revealing the motherboard, and I measured the voltage right at the input of the AC adapter socket and it read 3.88V.

So, it kinda rules out a connection problem which I thought would be.

I called the service center describing the symptoms, and they just concluded I need to change the motherboard which is real expensive. Doesnt sound convincing to me as it sounded like a lazy template answer.

I dont know what else I could do. What do you guys think would be the issue? Do I really need to change the motherboard? But shouldn't it be working if it runs on battery.? Kind of an overkill solution to me.

Appreciate your advice and suggestion.

 

[Laptop_Nerd]

Hi,

If you know your way around laptops and soldering electronic devices I would suggest to DIY. Motherboards doesn't come cheap, so if you're planning on buying a new motherboard might as well just buy a new laptop. You can try searching for part stores that sells the charging port of the laptop. There are also ton of video guides on Youtube on how to do this as well. I would also suggest trying a different AC adapter first and see if it will work or not. Also another test would be to remove the battery off the laptop and connect just the AC adapter and see if the laptop will boot up normally or not. If the laptop will boot up that could mean that there something else wrong with the laptop. But if the laptop will still not boot up that means it's really the charging port that can be damaged.

 

[YSFang]

Hi Laptop_Nerd,

Thanx for the quick reply. Definitely have tried removing battery and powering on with AC, but it doesnt power up as well. The AC LED indicator does not light up on the laptop.
I have other laptop adapters but they are 19.5V. I am afraid to try it as I fear may damage the laptop. I'll try to find another at the IT store and test.

I know basic soldering but havent done surface mount components before. And I wouldnt know my way around to tell which one is the faulty component.

I'll try to borrow a compatible adapter to test first. But, just wanna know, are the voltage measurements I have done gives any hint or not on what would be the likely problem?

Thanx

 

[YSFang]

Just got back from the IT mall. Turns out its a faulty Adapter. Phew!! Cheapest repair i could hope for. But still seems weird how come voltage measurement seems ok.
Thanx.