Reflowing Solder Under BGA Processors

I'm kicking off the Fix It blog with two videos that show extremely different techniques for reflowing solder. Both are repairs that you could do at home, but the first is as professional as it gets for non-factory rework, while the second is a great example of "just make it work." The first repair is so meticulous that it may actually discourage you from trying unless you are an experienced technician, while the second is a 21 second clip showing a known and somewhat effective work-around.

Runtime is 6:34



Reflowing solder with a heat gun is the "standard" homeowner fix for failed BGA (Ball Grid Array) connections. The tech in the video takes it a step further, removing the chip from the cellphone (desoldering at 608ºF or 320ºC or , using solder wick to clean the old solder from the processor and then adding a fresh new ball of solder to every contact. Then he cleans the old solder off the circuit board, and pre-coats all of the contacts with new solder. Finally the chip is placed back on the circuit board and heated to 572ºF or 300ºC until the the solder melts and reflows. Don't ask me how precise the temperatures on the heat gun really are:-)

The runtime is 0:21



In the second video, the we see the classic burning alcohol trick in the shortest form I've seen. The commentary is by a third party (mother?) who is wondering why there's a little tin cup with an open flame sitting on the motherboard of the laptop computer. BGA solder failure was a known manufacturing defect on some runs of Apple iBooks and IBM T series laptops, and probably others besides. People worked out that the video processor BGA contacts were the problem by physically pressing on the chip and seeing their video work. The first attempt at repair is usually jurt jamming something non-conductive between the chip and the case to keep the contacts pressed together, but that fix usually stops working after a while, so reflowing the solder becomes the only solution.

The classy fix, removing and reapplying the solder is no doubt a more reliable repair, but I wouldn't want to try it on a chip with hundreds of pins on a serious computer processor, rather than a cell phone chip. The classy fix also requires real skills, steady hands, a good soldering iron and heat gun. The alcohol kludge only requires a penny worth of alcohol and a tin to put it in.