G4 Random Shutdown

I keep experiencing a random shut down with my iBook. The only way I can get it back up is by disconnecting the power plug and battery, then reconnecting. Sometimes I have to enter mac-boot to get the system to run. The other day the screen on the book went black while I was hooked to a flat screen via VGA I could still see the flat screen but not the book screen. I removed the battery and tried running the book on the power cord but the random shut down became more problematic. Does anyone know what this might be or how much it may cost to fix?

This unfortunately sounds like the logic board issue with g4 ibooks at work again. I assume that the computer doesn't actually turn off it just drops the display to a brightness level that is barely legible. Sometimes not legible at all. If you are still under warranty, then send it in for repair, if you are not under warranty the cost of the logic board and the time it takes to replace is not worth it at least it wasn't to me.

There are some hacks that can be found on google, where a little piece of gasket material is placed somewhere on the logic board to disrupt the constant heat, but this method is unproven and not suggested by apple (though they did use this method from time to time on non functioning units without notifying customers as some customers claimed)

I believe for a time the logic board issue was under and extended manufacturers warranty but I'm not sure if it still is.

Google/forum search "G4 ibook logic board" to find some threads about it to see if you are experiencing similar symptoms.

I believe this is the issue that milessthomas was referring to.
Check the ranges of serial numbers to see if you've got one of the problem machines.
http://www.apple.com/support/ibook/faq/

Thanks for the info. My prob. sounds very similar to the logic board issue. I have noticed the machine drops when I move it or tweak the back of the case. Currently my machines monitor is blacked out. I'm using the book with the VGA connection. I'm gonna back everything up and and try not to move it or shut the monitor to hard. Time to save up for a new book.

Thanks again.

i've heard of bad ram causing this problem.

Fyi

The fan of death showed it's face yesterday. I decided to take her apart and shim the chip. It worked for now. I'm backing everything up. Lets see how long it lasts.

Some helpful links I used for shimming.


Link 1

Link II