Fan problem: Overheats, but doesn't turn on the fan.

Ok, I've a problem with my iBook locking up and freezing the Display stays active, and I can see whatever I was displaying at the time.

To, diagnose... I put the iBook on the cold concrete floor, and ran the TimeMachine backup... Works great. Runs to completion.

Locks up when I run Timemachine backup with the laptop sitting on a table.

I've decided, it needs to have the heat transfer goo replaced on the heat sinks. But, I'm a little perplexed about why the fan doesn't come on. The computer certainly feels hot enough.

Does anyone know, if the fan is "multi-speed" or if its just a one speed fan?

I've booted up, and ran the diagnostics... and It turns the fan on... and it does turn on. But, from what I can tell. It only comes on at "one" speed... e.g. High.

If the fan, is supposed to be multi-speed... then I probably need to replace it too. But, I can't seem to find out anything about the fan.

I will probably also try to get the G4fanControl program, and turn the fan on at a lower temperature. Seems with the new/larger HD I put in it is running hotter.

Does anyone know if the iBook G4 Fan is multi-speed? Last 4 of the G4's S/N are "JQHV"

Model number looks to be A1055. I don't see anything detailed about the fan operation when I look up the computer specifications.

Installed G4FanControl. from tinkering with its setting, I don't see that the fan is multi-speed. Now, I can get the fan to kick on at lower temperatures, which is good. I've also touched the power pins on the video related chip to re-flow the solder to make sure that isn't the problem (http://www.xlr8yourmac.com/tips/iBookG4_...)

Latest, is I can get the machine to lock up at will when I run anthing iTunes/Verify Permissions/etc that accesses the disk. I'm now thinking the new disk drive is bad. Any suggestions for further testing to confirm that is the problem? I noticed last night when running the "verify permissions" that the iBook became extremely hot where the disk drive is... then, it siezed up with whatever was last displayed on the screen stuck there. When I, did the powerbutton reboot... it did boot back up, and showed the usual info on the screen... but when I tried to run anything that accessed the disk drive it immediately locked up.

I will download the SMARTreporter ( http://download.cnet.com/SMARTReporter/3...) to see if it reports anything too.

re-gooed the heat sink to uP Video etc. G4fancontrol said all the temp's were less than 50deg(don't know what scale G4fancontrol uses)... When all of a sudden the harddisk started spinning faster... then shortly after that it locked up.. yet again.

I now have a SMART disk monitor running on the computer to see if it gives an error.

Thanks,

Dave

Note: I can't seem to "add comment" to this question from my usual PC.