How to fix your broken G4 ibook logic board

G4 ibook motherboard fault.

There is a design problem with the logic board in some Macintosh G4 ibooks. It seems to  appear after a year or more in some machines. After being on for a few minutes, they get a blank black screen, the fan turns on, and the computer freezes. You might think it is a problem with the display but it’s actually a problem with one of the chips on the main motherboard. This article describes the problem and how to fix it.

What models are affected?

After doing this survey which involved over 300 faulty g4 ibooks it appears all ibook models are susceptible to this problem. Thankfully the power books don’t have the problem. In fact the powerbooks from this era are a great design, the 15 inch Aluminium powerbookfrom this era is one of my all time favourite macs – I still have one.

The original 2003 ibook G4′s (800/933/1Ghz) have the fault. The “Early 2004″ (1Ghz) models up until Oct 2004 have the same motherboard.

The 60G (1.2Ghz) “Early 2004″ model and all the “Late 2004″ model ibooks (1.2Ghz/1.33Ghz) and Mid 2005 (1.33 and 1.42Ghz) have built in airport extreme which means a different logic board –  but they still have the fault!  Even models with the new logic boards are affected.

What is the fault?

The fault consists of one of the chips heating up and cooling down each time the computer is turned on and off, so that eventually a small stress crack appears on one of the pins of the IC. This means the display goes blank and the computer freezes. If you press the plastic case of the ibook in just the right place, it can put enough pressure on the chip so that the pin makes contact and the computer will power up again.

The Danish Consumer Complaints Board did some investigations and confirmed the fault. Here’s a report in the form of a pdf document with close up pictures of the fault here:

Here is a photo from the paper. You can see the thin black line below the lead which is a crack in the solder.

My ibook is indeed just as the article describes it. The little chip gets hot, and if I press my finger on the chip, it works! Take my finger off, it stops working!
I rang Apple Australia and they don’t acknowledge that the problem exists. They have officially ‘never heard of it’.

The repair:

You need a fine tipped soldering iron to heat up the top few pins of the chip one by one and resolder it to the logic board. Press the chip down while you apply a very clean and fine soldering iron tip to each pin.

This is a very complicated ‘how to’ a bit outside the scope of many people but it may be interesting to some. Don’t attempt this one unless you have had lots of soldering experience – or you are ready to say goodbye to your G4 ibook if something goes wrong!
Here are some pictures:

The G4 ibook with the bottom case off. The offending chip is circled.

Here is a closeup of where I have soldered the legs of the chip. You can see the base of the top pins are shinier and a little fatter from the new soldering. I soldered the top 3 or 4 pins on each side, but it’s only the top 2 pins that the fault occurs with as they are the main power pins. I applied a little more solder to the joint as well, that’s why it looks a bit lumpy.

The IC:

As pointed out in the discussions below, once your ibook is fixed,  or if your G4 iBook has not yet developed the fault, you might want to take out $10 worth of insurance by buying this little app. Then you can set the temperature that your fan turns on a little lower to keep the ibook cooler.