iBook G4 crashes when moved

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Joined: Mar 17 2005
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Hi all,
I just won an iBook G4 800MHz on eBay that crashes when moved (I haven't even received it yet.) The seller said it was diagnosed at the apple store as a logic board failure. I am going to buy a new logic board and install it (I've been doing this sort of thing for years so it's not a big deal for me,) but I don't see how a failing logic board is sensitive to motion unless one of the components on it is not soddered correctly. Does anyone know what causes this, as I could possibly just look into repairing the logic board itself or perhaps fixing the logic board and then selling it. Also, does anyone know if the G4 800 iBook can take any G4 12" logic board, or does it require only logic boards from the 800/1000 Mhz family?

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iantm's picture
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Joined: Apr 2 2005
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iBook G4

As for the failure path, crack open the bottom case, and remove the lower emi shield. five bucks says that a fair number of the logic board screws are broken or the frame is cracked. 90% of the time when a portable locks up due to movement, it's generally due to the board not being secure, or having metal objects (screws) floating around between the emi sheild and the board.

The 800 mhz G4 iBook will only work with the 800 mhz/1ghz logic board, the 1.2 and 1.33 ghz logic boards utilize different frames, top cases, optical drive ribbon cable, lvds cables (weird, I know), and the hard drive assembly connects to the board way differently on the 1.33 than any of the other series.

With the 1ghz board, the 56k modem will need to be replaced (it's a different, smaller assembly on the 1ghz model than the 800 mhz). The fan will also need to be replaced ($5 part from your local apple repair shop - ask for the fan for an early 2004 iBook G4 - they should know what you're talking about)

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- iantm
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Joined: Sep 23 2005
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GPU?

A VERY common and well documented failure of these logic boards is the solder joints on the GPU fail, while normally this would not be too big of a deal to fix, the GRU's on these boards are affixed with a ball grid array, instead of pins, so the only way to even see which points are failing is to scan it with an x-ray machine. That being said however, a very common (and seemingly working) fix is to just open the case and put a shim in the chassis that applys more pressure to the GPU. I thought that i had been reading about this very thing on here just a few days ago? At any rate, i know there is a website out there shoming how one person resolved this issue with just shimming the board... if i can find it i'l come back and post a link.

/Bill

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Joined: Sep 23 2005
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links...

heres the site i was talking about:

http://www.powerbook-fr.com/ibook/bricolage/repair_g3_video_en_article797.html

and the thread on the fritter from a few days ago:

http://www.applefritter.com/node/10193

iantm's picture
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One little issue

On the iBook G4's, in an effort to reduce these issues, Apple put the GPU on the topside of the logic board, and the heatsink is secured on top of it.

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- iantm
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oops...

sorry, i was thinking about the early G4's, and the G3's.

my apologies.

/Bill

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Joined: Mar 17 2005
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Hi everyone, Thanks for the

Hi everyone,
Thanks for the replies! Since the pressure trick (which I came across last night actually) won't work, does anyone know what logic boards it can take? For example, could I just drop a 1.33GHz logic board in there and call it a day or am I limited to 1GHz logic boards? I have done a lot of work like this before so installation is no big deal, and since I bought the computer so cheaply I don't really care about price either. I will have more info about it once it arrives.

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look at my first post

I gave all the info on that in my first post in this thread.

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Yes, you did, and you did an

Yes, you did, and you did an excellent job of it. I don't know how I missed that, sorry. Thanks for the great info!

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Anytime

If you have any iBook G4 questions, feel free to pm me. I know more about the iBook G4 than I'd really like to. (my days are spent tearing them apart and repairing them)

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- iantm
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pressure fix

here's a pressure fix i got to work. i posted it in the other thread, but thought it may be of use to folks who may find this one.

http://www.coreyarnold.org/ibook

hhr
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Joined: Oct 19 2007
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iBook G4

We are conducting an investigation regarding the faulty logic boards in the iBook G4 computers. If you would like more information regarding this matter please contact me at