Laptop Electrical Circuit

[Jawshh]

Hi,

I have an Acer Aspire 5570Z laptop. I think the motherboard has a short ciruit. My friend diagnosed it for me with a multimeter. Also, my adapter contains a led. When I connect the adapter to the laptop, the led fades and when the adapter is disconnected, the led becomes bright again. The laptop doesnt turn on without a charged battery.

So, my question is, should i get a new mobo or can it be fixed?

Thanx

 

[Kcircyrd]

No. Get a good used laptop. Lenovo Thinkpad, HP, Asus. Toshiba. Avoid Acer, Compaq, Sony, and any laptop in the lower half of their price range.

 

[Jawshh]

Hi,

Do you know where i can get these used laptops other than ebay?

I live in Mauritius

Thanx.

 

[Kcircyrd]

We buy ours from third parties. We get most of them from the two main Thinkpad sites, from PCSurplusonline, and others. Usually, the people I deal with specialize in one or two brands and some even limit themselves to certain models.
For Instance, we deal with certain IBM and Lenovo Thinkpads... 600X, T30, T41, T42, T43, T60, T61, X31, X41, G40, R40, R50... because we know them and know how to repair the minor problems.
We know people who specialize in Sony Vaios. Others who focus on HP Windows XP machines... and so on.

 

[strategic]

The laptop doesnt turn on without a charged battery.

Are you 100% positive that it's the motherboard and not the adapter? Can you get your hands on another adapter to try? I've done that between an HP and a Toshiba, the voltage varies +/- 1/2 volt but they are pretty much generic. I would try that first

 

[lamo]

Jawshh, you have short circuit in 19v bus. you don't need the schematics for this laptop. such problem is repairable without schematics. just check the 19v line and find short circuit to gnd.

 

[Jawshh]

@ Kcircyrd, thanx for your info. Can you please let me know more of those third parties and the other sites. And, is the Gateway brand laptop worth buying? Thanx

@ Strategic, yes i tried with another adapter and it doesnt work:dead: . I am sure its the motherboard. But thanx anyway.

@ lamo, I don't know exactly where the short circuit is but I know the range it is found on, I tried to look for discolored parts or burn smell but i didnt find any. You have any idea how i can find the short circuit? And if i manage to spot it, how can i fix it? Thanx

 

[lamo]

well, you can do a burning method. but yes, try to find some people, who know how to detect burned capacitors and mosfets.

 

[desigabri]

A way to find short circuits is to look for hot components after some second of connection. Think that you are using a 65W or 90W power adaptor...that power can't go away without produce some overheat. It could be a component of the voltage regulator or the battery circuit because if the problem was after the voltage regulator You shouldn't have a short circuit to the power line.
The best should be to have the board free, the up side as the down side. You should remove every removable parts as MEMORY, CPU, MODEM and so on and use the freeze spray to freeze at the first the components next to the power connector and the voltage regulator places. You don't need doing that in one time but You can try one by one place.
This only if you aren't able to find the hotest component by yourself touching the board with your fingers (pay attention: you could burn your fingers )))))
Remember that if a part is usually hot it should have a dissipator to protect themself. If you find a part very hot after some seconds and the part doesn't have any kind of dissipator you can't be wrong about it. The short circuit protect every other part of the board but the real problem is for the tracks that aren't made to substain that power. So be carefull not to go over some time of power supply. The freeze spray lets you see the overheat points in some seconds without touching components and you could do it place after place waiting some minutes between the tests.