My daughter's clamshell iBook was an ebay purchase. The seller said it was pristine, but within a day or two of receiving it, a six year old girl was frustrated and tearful about the sound that would come and go. Using external speakers through the stereo audio port would sometimes work (or iPod earbuds), but not reliably. Sometimes one could press on the case next to that port and the sound would come back. After a few months of this, I disassembled the iBook, got out the dissecting microscope and saw that many of the leads on the IC next to the audio port had lifted from the board.
I have a very nice soldering kit, so with it, a coffee-free morning and the scope, we carefully resoldered the chip to the board -- kissing each lead until the solder below melted. Sound was completely restored.
I've currently got a G4 iBook that will blink off when lifted from a table. I've thought it was a bad battery contact ... now I think I need to walk the boards to look for more loose leads on chips. Many thanks for the article -- Legos and Metallica: never thought there was a connection there.
What someone else attempted to describe is thermal hysteresis (or thermal fatigue / annularization) of the solder, where the heat/cool cycles will propagate minute imperfections of a solder joint into cracks that eventually lead to intermittant open contacts -- and a faulty circuit. Used to be the most common failure of the power Caps in the 128K/512/Plus series of Macs -- and Pina's 'Lost Mac Scrolls' helped us salvage many a goner Mac. Looks like this problem will never go away completely so long as we have solder and heat. Maybe once we go to solid state 'hard drives' and LED displays, a lot of that heat will be managed better -- but ANY electronic device will always have some risk of this aging phenomenon. The old tin/lead is stronger than tin/silver/copper now in production -- we'll have to see if going green means filling landfills faster...
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Surface mount chips all can have issues
My daughter's clamshell iBook was an ebay purchase. The seller said it was pristine, but within a day or two of receiving it, a six year old girl was frustrated and tearful about the sound that would come and go. Using external speakers through the stereo audio port would sometimes work (or iPod earbuds), but not reliably. Sometimes one could press on the case next to that port and the sound would come back. After a few months of this, I disassembled the iBook, got out the dissecting microscope and saw that many of the leads on the IC next to the audio port had lifted from the board.
I have a very nice soldering kit, so with it, a coffee-free morning and the scope, we carefully resoldered the chip to the board -- kissing each lead until the solder below melted. Sound was completely restored.
I've currently got a G4 iBook that will blink off when lifted from a table. I've thought it was a bad battery contact ... now I think I need to walk the boards to look for more loose leads on chips. Many thanks for the article -- Legos and Metallica: never thought there was a connection there.
What someone else attempted to describe is thermal hysteresis (or thermal fatigue / annularization) of the solder, where the heat/cool cycles will propagate minute imperfections of a solder joint into cracks that eventually lead to intermittant open contacts -- and a faulty circuit. Used to be the most common failure of the power Caps in the 128K/512/Plus series of Macs -- and Pina's 'Lost Mac Scrolls' helped us salvage many a goner Mac. Looks like this problem will never go away completely so long as we have solder and heat. Maybe once we go to solid state 'hard drives' and LED displays, a lot of that heat will be managed better -- but ANY electronic device will always have some risk of this aging phenomenon. The old tin/lead is stronger than tin/silver/copper now in production -- we'll have to see if going green means filling landfills faster...