Nestamicky and others in this group want to know how I've successfully
reflowed the ball grid array (BGA) solder to solve video chipset problems in
G3 and G4 iBooks and some G4 PowerBooks. I've also used the same technique
to reflow the solder and fix the G4 iBook U28 chip problem, and a loose G5
iMac video chip.
First, despite the fact there are a couple of companies that advertise
reflows on eBay, successfully reflowing BGA solder is an art, not a science.
Not even a megabuck reflow station with flux flushing and X-ray capabilities
can successfully revive a computer or X-Box or other device with a
BGA-installed video chipset that has one or more broken joints. I know, I've
paid hard cash to learn that a professional reflow cannot perform a miracle,
though it succeeds in enough instances to make it appear that way.
That's where art comes in. And the art derives from experience and learning
everything you can about a particular logic board in a particular machine.
If you pay close attention to an iBook, say, and patiently examine it, test
it, stress it, and run a myriad of trial and error procedures, sooner or
later you'll arrive at an "aha" moment where you understand whether it can
be repaired successfully using the reflow method, or not.
That's about all I can say. If an iBook makes a chime sound at startup, that
is a sign of a successful power-on self-test (POST) that indicates the basic
machine is OK. (But I've successfully revived iBooks that refused to chime,
too, just as I've failed to revive iBooks that did chime.) The next thing to
do is run the model-specific Apple Hardware Test. That will tell if the
logic board has a video or other problem, assuming the board will support
complete booting and then operation. If the board chimes and then crashes,
it could be anything. But bad video will shut down a laptop every time, even
if it chimes and begins the boot sequence. Beyond all this, the only way to
figure out what's wrong is to play around with a completely assembled iBook
and gather clues.
One technique I use is to remove the iBook's bottom case and inner shield so
I can position a screwdriver handle directly under the video chipset. Then I
attempt to start the iBook and boot into Open Firmware, which has much less
demanding video requirements than an OS boot. If the OF screen doesn't come
up when I hold down Command, Option, O and F, I try it again, putting gentle
downward pressure on the left palm rest above the video chipset. (I'm
careful to not exert too much pressure because the fragile hard drive is
directly between the palm rest and the video chipset.) Usually, this gets
the OF screen to appear.
Then I clear any corruption caused by previous aborted boots or bad-video
shutdowns during starts by typing these three lines, hitting the
enter/return key after each line is typed:
set-defaults
reset-nvram
reset-all
Quite often, the iBook will chime, start, boot and run perfectly when I
finish this sequence and hit enter/return the last time. Sometimes I have to
keep pressure on the chipset with one hand while I'm typing with the other.
Sometimes I have to play around with this process until the right amount of
pressure elicits the OF screen and subsequent successful boots. Sometimes I
have to use lots of pressure, just short of making the hard drive do
zing-zing noises.
Once I get an iBook running and it reaches a stable temperature, I usually
can remove the pressure as the heat has closed the broken solder gap(s). I
then let it run for hours while I run the Apple Hardware Test and/or the
appropriate Apple Service Diagnostic disk (G4 and G5 models), and watch for
screen artifacts and syptoms. If arcing caused by broken joints has caused
internal video chipset damage, it will show as an error during the AHT and
the test will stop at that error. That error usually is not fixable with a
reflow. So I stop right there and don't waste any more time on that logic
board, except to try one reflow in case the error was caused by a broken
solder joint and not irreparable damage to a video trace. (Some people have
had the chipset replaced with a known-good one, but that's way beyond my
capabilities and financial resources.)
I also manipulate the iBook during testing and while it's running the AHT.
Sometimes all it takes is a slight lifting on one corner to cause video
artifacts to appear or invoke a shutdown. But what happens is part of the
clue-gathering process, which can go on for hours until I'm satisfied the
iBook has told me all it can.
The process is time-consuming, frustrating and physically taxing (scrunched
over for hours on end, dealing with tiny stuff), and I only do as much of it
as needed. What's worse, all too often no amount of time spent can bring
success as there often are multiple problems that I have neither the tools
nor parts to resolve.
That said, anyone who's interested in the G4 iBook U28 chip issue can learn
about one person's "fix" here:
