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ojfd

macrumors 6502
Original poster
Oct 20, 2020
283
201
Bought a used 15" PowerBook G4 A1106. Upon startup it behaves very strange. I consider myself a power user, but in all my years on a Mac I haven't seen anything like this.

There is no internal drive, starting from external FireWire disk. Machine connected to mains. Battery is, of course, dead. I am not sure about the PRAM battery, but I don't want to spend any money on replacement yet, not knowing if it helps.

Here's how it goes:

Press power button.
Fan kicks in at full speed.
One long-ish beep.
Led near the latch blinks a couple of times.
Startup chime.
Machine boots into Open Firmware.
I type 'mac-boot'
Long wait time until it finds the external drive, then boots into OS (Leopard). If I press 'option' key right after 'mac-boot', I land in device selector, where I can choose my FireWire drive.
Date and Time is incorrect (set to default, I guess).
I connect via WiFi to time server and let the date to be set.
So far so good.
Now.
Pressing Power button does not initialize shut-down/restart etc. dialogue - I have to do it from the Apple menu.

Starting up again, trying to reset PRAM. (cmd-opt-P-R).
Fan kicks in at full speed.
One long-ish beep.
Led near the latch blinks a couple of times.
Startup chime.

Keep holding cmd-opt-P-R keys.

One long-ish beep.
Led near the latch blinks a couple of times.
Startup chime

Keep holding...

One long-ish beep.
Led near the latch blinks a couple of times.
Startup chime

Repeat 3 more times.
Landing in Open Firmware again.
Type 'mac-boot'.
As above, boot into OS.
Date and Time is incorrect again.

I can do this until I get sick - it's always the same result.

I've tried "remove RAM, add RAM, reset 3x PRAM" trick - no change. And it's always beep, blinking LED and then chime between the PRAM resets.
I've also tried, in Open Firmware:
Code:
reset-nvram
set-defaults
reset-all
No change.

If I press the power button while in Open Firmware or anywhere else, nothing happens. I have to pull the power plug to force the machine to shut down.

I've ran out of ideas. Dead PRAM battery seems to be the only remaining variable.. I've only owned desktop 68k/PPC Macs before and dead PRAM battery usually ment black screen and Mac that "plays dead". Behaviour of this PowerBook G4 is new to me.

Has anyone of you ever encountered something similar to this, especially with PowerBook G4's of that generation? Is it normal or is it indication of some damaged hardware?
 
Last edited:

joevt

Contributor
Jun 21, 2012
6,625
4,063
If auto-boot? is set to false then it would cause Open Firmware to always open. Check the result of printenv. But I think reset-nvram should change that?

Can you measure the voltage of the PRAM battery?
 

ojfd

macrumors 6502
Original poster
Oct 20, 2020
283
201
This is what I get. auto-boot? = true, system date and time = 01/01/1904 ..
I can measure the PRAM battery, but only if I tear it apart.
EDIT. Just did it. Measures 3,67 Volts.
 

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Last edited:

ojfd

macrumors 6502
Original poster
Oct 20, 2020
283
201
And, by the way, Apple Service Diagnostic 2.5.8 reports that all tests have passed with the exception of Temperature sensor neat trackpad.
 
Last edited:

ojfd

macrumors 6502
Original poster
Oct 20, 2020
283
201
Some more info. It is possible to boot into Target mode after this sequence

Press power button.
Fan kicks in at full speed.
One long-ish beep.
Led near the latch blinks a couple of times.
Startup chime.
Machine boots into Open Firmware.
Type 'mac-boot'
Press and hold "T" key.
FireWire logo appears on display.
 
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