Ever hear of REFLOWING solder?

They say that my model of Acer laptop (5520) has a problem with breaking solder on the NorthBridge, which produces the symptoms which I have been seeing. (after 3.5 years of dependable service)A rebooting loop every 3 seconds. According to some "experts" with similar problems, they have tried a radical solution to fix the problem.

Ever hear of REFLOWING solder? IT BASICALLY MEANS THAT MY LAPTOP MIGHT GET FIXED IF I COOK THE MOTHERBOARD IN THE OVEN at 200 degrees Celsius. This is a KEY instrument for me, as I use it 90% for all of my computing. The video display was still bright and everything else was working fine. I'm on my tower right now.

So has anyone here BRAVED such a thing ????????????

Here is a link to this insanity. http://www.wimsbios.com/forum/topic11831.html

I think it is better to try and ZERO IN on the NorthBridge with heat rather than cooking the entire motherboard.

Dan

Thanks Radman !

Dan

not trying to bust yer balls but you have 30 yrs experience and dont know what a "northbridge" is?

its close to the CPU. its a part of the mobo that is a bridge between the FSB, AGP and RAM. the other busses are typically bridged via southbridge. think of the northbridge as a high speed intersection or runway between those parts; not a good analogy but none really are.

Ok. I'm back on the laptop now. Seems that I can boot it if I hold it sideways and open the CD door at the same time. Weird eh !! Not good at all. Not dependable enough to use for the "on location" firewire recording I was planning for it. And I was looking for a 500 gig hard drive for it just earlier today !! Not good at all.

Dan

buy a mac. i'm not saying that to start anything or poke you either; i love PC's and macs both and i am typing on my PC right now. i would NEVER EVER location record for $$$ via firewire with anything running windows, not even a radically stripped down XP.

of course, i would never location record for $$$ with any laptop at all, even a mac. i use a $200 mac desktop for that, an old dual 1.25ghz G4 with a couple gigs of ram does the trick. lives nice in a six space rack.

this is a major part of my income, and i take it very seriously.

Reflowing solder is something that happens around here all day long. It's not something I do myself and haven't actually watched it being done but we're working on circuit boards and I'm certain they focus in on the problem ICs.

When it comes to ball grid array parts it just doesn't work. I couldn't count the number of power PC chips I rejected simply because the soldering process didn't work right and they end up in the scrap bin.

What are "ball grid array parts" ?

Dan

Reflowing solder is common in electronics. You reheat the solder to get it to reflow around the connections. you can have cracked solder joints, crappy wave solder job etc and the contacts to a part may be flakey. It can often be found through close visual inspection, or if you know what component is flakey you just reheat its contacts.

Computer boards are often hard to impossible to repair this way because the boards are multi layered and the components may make contact at various layers, so reheating the connections to get back functionality is really hit of miss.

if you get back functionality turning the unit sideways, my guess is the component is fairly heavy, or the board or component is being flexed to make a contact.

That was actually super informative. Now I see why some modern circuit boards are so prone to physical damage from torquing (because of noncompliant leads) but can be made cheaper and smaller. Explains a lot.

Thanks!

I would consider this to be a very high risk thing to try. If the board is that flaky, it's worth a try before pitching it into the trash, I suppose.

If you do it, make sure you let it cool off thoroughly before moving it, and disassemble the unit so you only cook the motherboard. There are excellent odds that the other parts in the unit will not survive that sort of heat (such as the LCD display, and any thermoplastic, such as the keyboard keys).

If it were me, I'd first borrow a microscope and examine each visible solder joint very carefully, and have any suspicious looking joints hand-soldered by someone experienced in soldering high-density surface mount boards. If that fixes it, you're done. If not, fall back to the baking idea...

I dont think he was talking about trying to re-wave solder the board.

That would be a fail because they lacquer the boards after the initial wave soldering to prevent oxidation and to

pevent dust and dirt from being able to short between contacts.

You would resolder the suspected areas by hand only. You would also use a low watt iron and use heat sinking techniques where you could.

The normal methods of finding the problems are visual inspection, moving components to find cracked connections, using heat and cold, and logically thinking the problem through ruleing out what it isnt with deductive reasoning. Theres so many micro components on boards now though, especially on compact laptop boards, and the connections so small, if the problem isnt obvious, its a throw away item. The legs can even crack inside the components themselves and not even be a solder fail on the board.

Many laptops can be flexed. The casing is not that strong, its made to be light. Flex the case, you flex the board and crack solder joints. End of story. Someone sits on it or drops it, sits something on it, footballs the case, the units usually toast. A tech may get luckey fixing it but thats extremely rare.

This is exactly what I was suggesting: Examine the board and resolder suspicious looking joints... And, yes, there is a really good chance that the issue is a broken ball grid array solder joint or an intermittent bond wire inside an IC, or a via in an inner layer of the board that has separated from a buried circuit trace, which means it's not economical to fix.

A quote from the original post:

"Ever hear of REFLOWING solder? IT BASICALLY MEANS THAT MY LAPTOP MIGHT GET FIXED IF I COOK THE MOTHERBOARD IN THE OVEN at 200 degrees Celsius. This is a KEY instrument for me, as I use it 90% for all of my computing. "

If you're doing a "hail mary" on the machine....

The places where laptops typically go wrong won't be a part in the middle of the board. Odds of a BGA part developing a bad solder connection is close to nil. It'll be (in order of likelihood):

But, #2 is the easiest to verify. Unplug everything that you can (pull the hard drive, DVD drive, the wireless card if it's an internal card, and try booting it. Of course, Windows won't start, but you should boot into the BIOS. If that doesn't work, pull the memory and try again.

The next step is for the more brave. Pull it apart and try reseating any internal cables. If THAT doesn't work, see if there's an online disassembly guide, pull the motherboard, and try reflowing the peripheral connectors.

The powerup/reboot means that it's not passing its power up diagnostics. (tech alert - feel free to ignore.... Sometimes what can happen is that a flaky connection can cause a bunch of invalid interrupts to be fired off before the interrupt controller/vector table is set up... causes a crash/reboot. If you somehow manage to get past that at boot, then the stray interrupts get handled safely).

If none of that works, then baking the board isn't going to hurt.

Best of luck.

js

There are 2 more of these with the same symptoms on Ebay right now. I can't get it to boot any more. The fins leading to the CPU was full of dust. I cleaned them out but I suspect that the CPU may have overheated. The cooling system is interesting in this laptop. There is little vertical space, so they run the fan through some cooling fins (like a radiator) and the cool air travels down a copper tube...to the cpu I assume. I haven't removed the motherboard yet, but this is my guess.

I plan on doing a close inspection of the mb. Then I'll use my low wattage soldering iron with a solid tinned #22 wire wrapped around it to act as a very small tip, to resolder the suspect pin/s. However as already mentioned these boards could be 6 layers and without seeing inside it is a hit and miss.

Dan

Why don't you just buy a new laptop and save yourself the aggravation? I mean yeah a cool little fun project maybe..... but that is some fine detail work there..... you could easily damage something, bridge something as Radman said....overheat a tiny component, dry solder something. Is this the host PC for your DAW? If so you will be mighty upset if it craps out again, in the middle of your very best yodel take ever....or something equally important.

You mentioned it is a few years old......maybe it's just time to get a new one and then try to fix the old one with the pressure off, that it has to be right. Dunno....just me.

I didnt see that. Thats rediculous, you cant bake a board like that. Its not how you reflow a board and you'd damage every component on the board. Inside every chip you have micro wires that are soldered to the contacts inside the chips. Those would all unsolder themselves, plus getting those components anywhers close to melting solder will wipe them out.

Maybe, and I mean a "real big" maybe, you could use a toaster oven type deal to reaheat the contacts quickly. Quickly heat and quickly cool is the key. I'd never try it though. Re wave soldering is the only sure method and for the cost of doing that you could replace the board.

I'm also looking at the Dell Alienware line as PLAN B . Firewire and lots of speed.

Dan

yeah, cuz dell's are just sooper.

Since you use your computer for audio, this one might qualify for inclusion in the "Stoopid Audio Myths" thread. Sure, I've heard of reflow soldering. It's the way they make surface mount PC boards. But when they do it on the production line, they have the benefit of fresh solder and flux. I think thatt 200 degrees C is a bit on the low side since most modern lead-free solders like to flow best at around 225 degrees C.

Of course you shouldn't have to do this, but the RoHS laws have played havoc with electronics. Everybody seem to have soldering problems. There's a group which includes several audio manufacturers who have been working on getting an exception to the RoHS rules under the premise that unreliable soldering will cause more units to go into the landfills than when they used real tin/lead solder and made joints with a half-life greater than that of a Twinkie.

It might be fun to watch the caps explode.

It might be fun to watch the caps explode.

then detox your oven after the electrolite, parifin and oil ignite.

then detox your oven after the electrolite, parifin and oil ignite.

My wife has asthma. She told me NO !!!

DON'T WORRY. I

I'M NOT THAT STUPID ?

DAN

Here is the fix for my specific model.

[video=youtube;cBy7rOiQw18]

And another.

[video=youtube;hba5Ad879cI]

Here is a similar fix on a HP.

[video=youtube;ctHTF3oNdxI]

Dan