Damaged Motherboard Potential Repair?

[graham01]

Hi everyone

I have taken on a task to fix my friends laptop. It was dropped and suffered some bad damage to the screen and I accepted the challenge as I said it shouldn't be hard to source a screen relatively cheaply and fit it for him, however after looking at it I am fairly sure the motherboard is also damaged.

It is an Acer 5742 and is showing some pretty weird symptoms. It turns on for about 3 seconds, fan spins, blue lights show (no flashing - just on) and then it turns off again, so I just assumed the motherboard was dead as this is usually a pretty big sign. But it does do different things, I have noticed if the charger is plugged in, it will repeatedly turn on an off until the charger is removed, as opposed to when the charger is not plugged in it will only come on the one time.

If the battery is taken out for about an hour and put back in and turned on, it will come on for much longer, maybe about 1-2 minutes, in which the CPU and chipset get significantly hot, but still does nothing - no sound - no flashing lights etc.

I inspected the motherboard and found one of the capacitors was slightly lifted up from the motherboard and it appeared that one of its legs was not in connection to the motherboard, so I took it off and soldered it with a couple of wires to the board, but it still didn't effect anything.

I have added some pictures of the motherboard and capacitor I reattached the board, this capacitor also has a slight dent which looks like it has been caused by part of the casing hitting it when it was dropped.

http://i42.tinypic.com/2131xe.jpg

http://i42.tinypic.com/m9vijb.jpg

Thanks for looking!

[Mad_Professor]

Re: Damaged Motherboard Potential Repair?

You got a short somewhere on the board. Strip it down to bare board and test again, this includes ram and cmos battery too.

If anything, it's probably a broken trace or traces on the board, if that's the case depending on the severity and how complicated the silkscreen is, like for example you may have multi-lanes and you may not have the skill to repair it. To repair, sever the damaged trace and place a jumper wire from point A component if there is one to point B component, if it's that simple, that is.

And get a new poly cap for that damaged one.

Someone should chime in with a recommendation.

[graham01]

Re: Damaged Motherboard Potential Repair?

You got a short somewhere on the board. Strip it down to bare board and test again, this includes ram and cmos battery too.

If anything, it's probably a broken trace or traces on the board, if that's the case depending on the severity and how complicated the silkscreen is, like for example you may have multi-lanes and you may not have the skill to repair it. To repair, sever the damaged trace and place a jumper wire from point A component if there is one to point B component, if it's that simple, that is.

And get a new poly cap for that damaged one.

Someone should chime in with a recommendation.

Thank you for your reply, I have tried stripping it down to just the motherboard and still same thing. Is it definitely the symptoms of a short? That it stays on longer if it is unplugged for a while etc.

Regards

[graham01]

Re: Damaged Motherboard Potential Repair?

I have also looked closely all over the board and cant see any broken traces

[trebo]

Re: Damaged Motherboard Potential Repair?

you got the same symptoms as my acer travelmate 5320
after breaking it down and testing as much as I could test, and finding nowt (about five times)
borrowed a cpu off a friend and swapped it, and it came straight on
in you case it would be strange for the cpu to be damaged after dropping
but it would be worth swapping with a known good one if you can get hold of one, just to eliminate,

[graham01]

Re: Damaged Motherboard Potential Repair?

Hmm.. I think I just destroyed the motherboard even more somehow. I am not really sure what happened, but I took the CPU out to see what would happen without it, as soon as I plugged the battery in all the lights started to flash really fast, and smoke started to come off the board.. my room now stinks of fried components lol. I am guessing it is no longer repairable.