ATi IXP 460 BGA Repair

[vette3066]

My Acer Aspire 5102WLMi doesn't detect either IDE drive on boot almost consistently now. When it does, I/O error opcodes get thrown down not long after boot. After a bit of research, I've come to the conclusion that the ATi IXP 460 chip that controls said I/O has come loose from the motherboard. You see the laptop c-clamped to the table right now - it's pressing the IXP 460 chip to the board. In this setup I have yet to encounter a single I/O error (save the times I've bumped the clamp )

So I plan to reseat the chip. I came across http://forum.beyond3d.com/showpost.php?p=367012&postcount=6 that says:

Now about unsoldering them... I couldn't have done it without some help from a friendly Russian
What you need to make is a sort of a heatplate, as the whole chip has to be heated in order to be soldered (it CAN withstand soldering temps, just not for too long). What I did is make a 1x1x2cm solid copper block with a round hole on one of the the 1x1cm sides of it, slightly less in diameter than the soldering tip's needle. I filled the hole with AS3, hammered the needle in and lapped the other 1x1cm side, and viola - I have a heating plate.

I have available to me a small tube of AS5, copper heatsinks, soldering gun, plastic welder, laser thermometer, and household materials. I also have a few questions:

1. Am I correct in thinking the chip needs reseating
2. Is it safe to reseat the chip using this method (minus actual removal of the chip)
3. What exact temperature do I need to take the chip to
4. What kind of pressure should I apply, and for how long
5. How long should I keep the chip at soldering temperature
6. Once done, should I let the chip cool in ambient temps or should I use something like a fan

Thanks!

 

[Davros]

i did see a post where someone put a dead mobo in the oven and it came back to life
i'll see if i can find the link

 

[BRiT]

[H] recently had someone post how they cooked their Nvidia 8800GTX to get it working again ([H]ardThread). Others followed suit and got their broken Nvidia cards working too.

 

[vette3066]

I'm glad to see that this kind of thing has been done before and actually worked. I was worried I'd set myself to a pointless task.

Between the [H]ard link and this it's safe to say I need to bring the chip to 185-200C. At this point I think I'll still use the heat sink and soldering iron in order to keep most of the heat on the ixp460. I'm afraid gravity may screw with things if I place the two-sided motherboard in an oven.

Thanks again for your time and input. I'll let you know how it goes :smile:

 

[Grall]

A: I don't think a soldering iron provides enough wattage to heat a BGA chip consistently and evenly in any kind of reasonable timespan. You need to transfer the heat to the solder balls on the underside of the chip - and epoxy and glass fiber laminate (the materials of the BGA package) aren't terribly good heat conductors. A whole bunch of solder balls are out along the edges of the package, and those aren't covered by the epoxy "casing", meaning they won't receive any heating. So if there's a lose connection there you can't fix it this way. You need a heatgun to do this properly, and even then it will probably be very difficult. You'd likely need to break the chip off the board completely first before reattaching it. Getting it done by a professional would be preferable of course, but likely not worth the expense unless you find someone willing to do it pro bono.

B: why go to this much trouble over a crappy old laptpo? Get a new one instead, it'll be better than this one in every way... Even if you don't have much money, the cheapest lappy money could buy would be better than one that's a half-ish decade old... Your CCFLs in the screen's likely on the way of crapping out on you also, capacitors aging etc.

 

[vette3066]

You're right about the soldering iron. My dinky 30 watt didn't get me anywhere. I'm baking a chunk of steel right now to some pretty nasty temperatures hoping it'll get the chip beneath it hot enough. If this fails I do have access to a plastic welder which I should be able to use as a makeshift heat gun. I'm also inclined to believe the break is nearer the center of the package just based on what kind of pressure is required to make it function.

It pains me to see a piece of hardware become scrap due to such a small problem. I was in the market for a laptop to do some relatively basic things and I came across this for almost nothing, and it really is more than adequate. The screen is still brilliant and all the input/output works great. Yes, I'll probably go out and buy something four times as fast for $400 if I can't get this going, no big deal. But I'd much rather be able to save that money for something else. That's all.