G4 iBook won't boot, already shimmed

2 replies [Last post]
Joined: May 13 2006
Posts: 1

I've resurrected two G3 iBooks this week by shimming under the GPU, but I have a G4 iBook that also won't boot. I've put pressure under the logic board below where the GPU sits to squeeze it into the heatsink, but it still won't boot. All it does is run the fan.

Perhaps the GPU isn't really the problem in the first place.

I stupidly bought a 1.2GHz logic board on Ebay thinking it would fit in my 1.0GHz iBook. I now know better of course, but I'd rather not buy another logic board if I can get this one kicking.


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iantm's picture
Joined: Apr 2 2005
Posts: 709
fan spinning logic board failure

the fan spinning failure path of the iBook G4 has two possible remedies (unfortunately - this is not related to the GPU). Have you tried resetting the PMU? Sometimes this works, but is a temporary fix. The only way to permanently resolve the issue is to replace the logic board, and as you've discovered, the only logic boards that will work with the internal structure of the 1.0 ghz is the 800 mhz and 1.0 ghz logic boards. (assuming this is a 12"). The 1.2 ghz boards are weird, as they will NOT work in any other revision of the iBook G4 (this goes for the 1.33 ghz doubly so)


- iantm
ACPT & ACDT (long expired)
BMW Certified Technician

Joined: Jun 8 2006
Posts: 1
G2 12" motherboard

Sorry to hear from that you got the wrong board.... basically same thing for me... i could re-buy your G4 12" 1,2 ghz,it should work me.