Seem that it needs a thermal calibration. You need Apple-Service-Diagnostic CD V2.6.3 (for Mini & PB)- will be found here:.

https://web.archive.org/web/20170309102920/http://dreamsupport.us/downloads/apple-mac/Apple_Service_Diagnostic_Disks_25_GB/
(If link does'nt work directly, copy and paste it to your browser)

Boot from CD and choose "thermal calibration".

> https://web.archive.org/web/20170309102920/http://dreamsupport.us/downloads/apple-mac/Apple_Service_Diagnostic_Disks_25_GB/

The IMG and ZIP files have not been archived, as far as I can see.

2 weeks ago I've downloaded ASD 2.6.3 from there. I can share it (PM!) if it cannot found anywhere else.

Thanks for the useful tip. I've found it elsewhere on archive.org:

https://archive.org/details/asd.2.6.3

(special note: I used to work there :) )

I will burn it after it finishes downloading and give it a try.

best
t

Both ASD (OF) and ASD (OS X) say they do not support this machine.

It is an iBook G4 (PowerBook6,5) @ 1.07 GHz.

The docs on the 2.6.3 disc suggest it supports iBook G4 so that's kind of weird. The docs also suggest that the thermal recalibration procedure is only for G5 computers...

I've no iBook - only PB-G4. Maybe you'll need ASD 2.5.8, which supports IBook G4 (14") Early 2004.

On my PowerBook ASD 2.6.3 tests all thermal sensors and fans. This should be similar to IBook.
Thermal sensors are: TrackPad/CPU-Intrapid-bottom/CPU-bottom/Power Supply, Fans:Rear and left exhaust
Test shows what component fails (replace or repaire). During test ASD tries to recalibrate sensors, if possible. If not -> test fails and hardware-action is requiered.

Hi — yes, you are right. 2.5.8 boots on this hardware. However, 2.5.8 does not seem to offer any thermal calibration. So, I'm not sure this will help my situation with trying to use MorphOS on this computer without the fans running at 100%.

Please read what I've wrote above: There ist no seperate callibration tool for G4-Macs, as you have seen for G5-Macs. G4-"calibration" is'nt such a sophisticated thing as on G5-computers.
I have no IBook, but I think there are also seperate tests for Sensors and fans (as on PB), which you can choose.
Please run the Sensor- and Fan-tests (click them seperatly - all other off). During running these tests, ASD-prog tries also to recalibrate!!
In most cases "fan-calibration" is OK, if all tests passed. If a test fails, you know what component is foulty and has to be replaced.

Whoops! Sorry for being irritating.

Yes, I did run the fan & sensors test -- but didn't boot into MorphOS afterward.

Now I have booted into MorphOS (3.12) and the computer is quiet!

Thank you so much! I will be registering MorphOS for this machine soon.

Well... false alarm perhaps. Of course the reason the fans weren't running is because the computer had been off for a while and was cold. :)

Oh well.

That means under MOS they are running again with 100% after a while? You should check, if there is something runing in the background which schould'nt. (CPU-load?)
What's the behaviour under MacOS?