Cant turn on

If you have the problem with no chime, no screen light up, and fans at max, it may be possible to fix it. It is often a design flaw in the soldering process.
Press firmly down on the left of the mouse pad when you press the power button (or try holding it in your left hand with your thumb by the touch mouse and fingers under the mac pressing firmly on the bottom) if it chimes. or even boots when this is done you can find a shop that does soldering(micro soldering) and have them fix the chip thats lose. Or for a quick fix try this site http://www.coreyarnold.org/ibook/ he shows the most common chip that comes lose.
All but 3 or 4 failed iBook's that had the fans start and nothing else, seem to have this problem(that I've seen) but Mac refuses to say it's a defect in all country's but Denmark (because a official study was done there that proved it was a manufacturers defect that each time you power on/off the iBook the solder gets a little looser.)

My iBook decided to (most of the time) not start, and then when it did start up, it would shut down at random intervals. I tried all the various key sequences, tried starting up with the battery, without the battery, all with no success. 
There was only one tip that I stumbled upon (can't remember where or who the poster was--many thanks to them!) that did work. 
1. Unplug the power adapter from the iBook. 2. Remove its battery. 3. Let it sit for 1/2 an hour to an hour. 4. Press the power button several times, as if you're actually trying to start up the iBook. Make sure you do this WITHOUT the battery and WITHOUT the power adapter! (Yes, I know there's no power source and it won't actually start.) 5. Replace the power adapter. Try to start the iBook with only the power adapter and no battery. If this works, then replace the battery as well.
From what I remember, what step #4 is supposed to do is drain all residual power (from capacitors maybe?) from the circuitry and forces the power management circuitry to reset itself. There's a key sequence that's supposed to reset the power management circuitry as well, but it didn't work for me (no matter how many times I tried it). My iBook now starts every time with no fuss.

I hope this helps someone out there!

I had the same problem. Did the fan turn on after about 5 seconds at full power? If so it is a logic board problem and will cost ~$300 to fix if out of warranty. If you paid with a credit card check to see if they offer extended warranty coverage. Thank god mine did, so i should be getting mine fixed. Good Luck.

Try these in no particular order (except last 3) try command-option power this puts p-books to sleep (may trigger it to wake) (it could be asleep) Remove your battery and wait 5-10 mins then try to start up with battery in Remove your battery and wait 5-10 mins then try to start up with battery removed To zap PRAM On startup hold down the cmd, option, p and r buttons Hold till you hear boot up sound To zap NV RAM On startup hold down the cmd, option, n and v buttons Hold till you hear boot up sound To reset the screen on a powerbook: On startup hold down the r button - To force internal Hard drive to be startup disk On startup hold down the r button - until boot Disable extensions: Try power up-reboot with shift key down Last but not least try to startup with original MAC system startup CD If all else fails try to get to an Apple Store...unless it's a real hardware problem (fried circuits/damage they'll fix it for free!) Pray - believe it or not... it worked for me when I got down on my knees and prayed. Hope this helps