Laptop won't POST/ PowerOn after Thermal Compound Replacement

[cojocariuadr]

=OK this will be a pretty long post. I'd be really grateful if you guys could give me a hand.

Laptop : Acer Aspire 5742g-384g50mnkk

Very many models of this device it took me a while to find a specs page:

[url]http://notebook.miotec.net/product-4696/acer-aspire_5742g_384g50mnkk[/url]

Specs:

Mobo : Says it is a PEW71 not sure what that is but it looks very similar to this one:

[url]http://fmtek-shop.com/858-1806-large/motherboard-acer-aspire-5741-5742-5742g-model-pew71-l51-mbr5402001.jpg[/url]

The thing is it is the one with the curved like ( top right ) not the flat line.

CPU : Intel Core i3 named 380M 2.5 GHz

GPU: nVidia GeForce GT 540M

Now the story. Laptop worked fine, could even play games with it pretty chill, but one day it suddenly shut down. I found out it was BIOS set to shut down at 85 degrees which is very good, as I didn't burn my pieces.

As time passed, it would get hot very very very fast, even when I start it it whould go fast at 60 degrees, and soon 70 following when watching YouTube or a HD movie of 1080p. Also, when hot, the GPU could not process everything well, so it would jump sequences of the movies, which got me really annoyed.

2-3 days ago I figured out I got time, so I bought some Thermal Compound , not the best though but good enough, watched all the tutorials possible, then oppened my Laptop.

I found it pretty hard to get to the CPU because I just couldn't unplug the PSU from my Mobo and got me veeery annoyed, but decided not to try, not to break it.

Hardly Turned the Mobo, unscrewed the Heat Sink and the cooler ( all soldered in one piece ) and found a bloody mess of thermal compound, spread all over the GPU and CPU. I've read a lot about not applying much, here it was so much it took me about 2.5 hours to clean it all up. Like the damned bastard who assembled it had a diarrhea of compound that he decided to put it on that laptop.

I had to unstick the GPU protective cover, which was hard and left some glue on the GPU I had to clean later ( there was dried Thermal Compound beneath it so I had to remove it )

The CPU was even harder to clean, couse there was paste all over the 2 cores and also all over the pins, and most of the paste beneath was dried in big pieces, that would come out very hard. I had to pull the CPU out .

I know I sound rough but I was very gentile with all the pieces I assure.

I used ear cleaning sticks , 70% alcohol, some acetone for the glue from the GPU, and some glasses paper tissues to clean everything.

There are still remains of the old paste on some of the CPU pins, I couldn't get that out no mater what... but not touching them one with another as before ( everything covered up )

Finally after many hours of pain, I reassembled everything pretty fast, by the book, then pressed the power button and boom.

Laptop will power on for 3 seconds, then off. No post. Nothing.

I did hear about ESD after I did the operation, I was working on wooden table, feet on carpet true, but I was lucky to wear my 2 bracers as usual, one on both hands, ( steel on right, leather with 2 iron pins on left ) so I don't think it is the case. Also didn't felt any discharge, and always held things by the sides.

Mentions :

I have no other parts / laptops to check pieces with.

It's not the screen, Couldn't possibly be, Didn't touch it much, and it does the same with the screen unplugged.

I've tried the following things :

Every combination with/without CPU/RAM/HDD

This next part might be important.

With battery it will power on 3 seconds then shut down.

With AC cable, it will power on for 3 seconds, shut down, the repower on by itself and stay on for an undefined time ( long ) as first time it shut down after about 2-3 mins, and the second time I powered it off myself.

Can't remove GPU ( Soldered to the Mobo DAMN ) But I still got the Intel HD Graphics of 128MB so I guess the first post was anyway through the Intel card untill it boots the nVidia one.

One of the CPU pieces had 2 hole-like spots on the bottom right corner. They looked pretty big but were there right after I cleaned the thermal compound. Tried to clean them, but they wouldn't go away.

Searched on how to clear CMOS. Easy. Find clear BIOS jumper. HARD and stupid. There's no such thing on that motherboard I searched my ass out. Battery was soldered so I searched again and found out that shorting the battery will reset the bios. Did it once, twice, three times, same result. No post

Left it to short by the night, as I've heard some BIOS take a lot to reset completely, and now guess what ?

No it does not work.

It doesn't even power anymore.

Not on Cable, not on Battery, I press the button and nothing. It might be the PSU as I moved the cable a lot. An still, Battery was pretty much full so why not work on battery if PSU is damaged ?

Taking it to the shop will probably just make me pay for new parts + that guys work.

I've heard baking the MotherBoard could actually save it. Tried heat it up a bit with the hair drier but nothing happens. It won't power on anymore.

Thanks a lot for reading all this crap :D Wanted to make myself explicit so that no questions of what I already did would be asked. Hope I didn't miss anything.

[[EG] Pepper]

Depending on the paste, you may have shorted some of the CPUs pins.

If you did that, you may have killed your board and CPU.

[editline]12th January 2013[/editline]

What thermal paste did you use?

[cojocariuadr]

Well in my country things suck xD I don't have the tube on me now but I can tell later. True it might have been the paste. If i was smarter I could have just kept the old one. There was plenty. Not sure what paste it is but it looks pretty thick and cristal like.

Anyhow, couldn't short the pins. They were fully covered in paste before... true maybe a better paste, But when I applied the new compound, I did not spill anything around it. And even when I reopened, some was a little pressed by the sides, but none touched the pins.

[editline]12th January 2013[/editline]

And what effect do shorts have on CPU and Mobo ? Burn it ? Why can't it be fixed?

And why did it power up at first with no POST, and after the long CMOS reset, it didn't start at all anymore ?

[[EG] Pepper]

[QUOTE=cojocariuadr;39195534]Well in my country things suck xD I don't have the tube on me now but I can tell later. True it might have been the paste. If i was smarter I could have just kept the old one. There was plenty. Not sure what paste it is but it looks pretty thick and cristal like.

Anyhow, couldn't short the pins. They were fully covered in paste before... true maybe a better paste, But when I applied the new compound, I did not spill anything around it. And even when I reopened, some was a little pressed by the sides, but none touched the pins.

[editline]12th January 2013[/editline]

And what effect do shorts have on CPU and Mobo ? Burn it ? Why can't it be fixed?

And why did it power up at first with no POST, and after the long CMOS reset, it didn't start at all anymore ?[/QUOTE]

It depends on what's shorted really.

Have you tried reseating the RAM, CPU and GPU (if it's on a separate PCB)?

You'd probably be best off taking it round the computer shop. they will have the stuff to see what went wrong.