Here’s the victim - a PLCC EEPROM that’s rather close to a BGA module.  The EEPROM is circled in blue.  As far as prep goes, we removed an IDE cable and the nearby battery but other than that - not much, we even left the PCB mounted in the case.

The battery socket looks like high temp plastic so he’s OK, the IDE socket is cheap plastic so he’ll melt if he gets too hot, and there’s a nearby BGA chip.  Uh oh.  This is the guy you need to be careful with, too much heat/air and you can literally melt his balls and blow them away.  If that happens you’re screwed.  First timers and the paranoid might want to make a small foil shield to protect the BGA from excess air.  It would probably be OK if a few of the BGA balls melted as long as the air didn’t disrupt them.  We’ve done this enough that we think we can get away with it.




Fig 4 - Standard Heating Technique


When heating the device, you want to come in at an angle to heat the pins.  You should also circle around the device to try to get the pins evenly, but if you absolutely need to avoid blowing air in some direction you can get away with avoiding that angle.  At highest heat and highest air, we started out about an inch away and moved back over the next few seconds to about 2 or 3 inches away.  You could see the heat gun’s orange glow reflected on the top of the IC.

The total heating time was about 25-30 seconds and after about 10 seconds we began nudging the EEPROM with a set of long tweezers.  Once the solder melts it will stay melted for at least a few seconds with no heat so once you see the device move, pull the gun away and grab it up with the tweezers, removing it from the solder pads.  In this case, a nudge pushed it off it’s pads easily so we picked it up before it could re-solder itself to anything else.

Continued on Next Page…

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