Sony VGN-FS980: broken joint or BGA?

[golemmaster]

I have a Sony VGN-FS980. It has been sitting in a box for a couple years. A "one of these days / when I have time" box. Well, I have some time now.
It won't POST. I have found that if I flex the board in just the right way, it will POST and boot. I thought I had found the area that seems to need the flexing but it is still difficult to get perfectly consistent results. During my experiments, the board needs more and harder flexing to get it to respond. The problem is getting worse. I somewhat expected that. I've prodded and pressed down on all the parts hoping it was just a smd resistor or cap or something I can retouch with a hot iron. Maybe a BGA problem. Dunno.
ANYWAYS....
What do you guys think of me waving a hot air / heat gun around on the board and try to get whatever joint to reflow itself? Or other suggestions...?

[thesloc]

Re: Sony VGN-FS980: broken joint or BGA?

What do you mean flexing? like literally adding pressure to get video?? If lights come up, but nothing else it's probably a bga problem.

And yes, it needs to be reballed or at least reflowed.

If you're going to wave a hot air gun...you WILL need a non-surface thermometer or a thermocouple.

Tmax should be around 230C.

Don't forget to cover the other components with aluminum foil tape or kepton thermal tape to avoid damage..

[golemmaster]

Re: Sony VGN-FS980: broken joint or BGA?

Yes. Bending the board. Power light lights-up. No POST or boot unless I bend the board a certain way.
I have the board out of the laptop. I have my fingers on either side of the board and chips. If I press directly (squeezing / pinching toward the board) any of the BGA chips, it doesn't help. Only bending the board does the trick.

Fixing this laptop is an experiment and a "feel good" project. I shouldn't be worried about breaking it completely, but it looks so promising. I would definitely feel bad if I destroyed it in the process.

How about the old bake it at 400F / 204C (temp needed to melt / reflow solder ?) trick? What temp do the plastic connectors melt or deform? Crazy Idea?

[thesloc]

Re: Sony VGN-FS980: broken joint or BGA?

The melting point of lead-free solder is 217C, and for a proper reflow you will need to push it to 230C for about 30 seconds...

I'm not sure about the plastic components, but simply reflowing it like that (and even if it works) will be short-lived. I'd give it max 1 month before it breaks again. Most likely within a week tho...

[skywalker]

Re: Sony VGN-FS980: broken joint or BGA?

Thesloc is totally correct. Here is a typical reflow profile for you to look at

[golemmaster]

Re: Sony VGN-FS980: broken joint or BGA?

I remembered the 217-230c info after I posted. :/
I don't have the equipment to try either repair right now.
Well crud. I'll keep thinking about it.
I'm not perfectly certain that its a BGA problem. But I guess the odds are it is.

[golemmaster]

Re: Sony VGN-FS980: broken joint or BGA?

Just FYI....
FixMyGPU.com and FixMyGPU on youtube.
Interesting vids to watch and pretty good prices on the service.
He does full reball only. Not reflows.