Powerbook G4 issues...

[alexra1205]

Well, first off, I'm new here, so apologies if I'm doing something wrong.

So, yesterday I grabbed my PowerBook G4 12 inch to do some ISO burning, setting everything up, etc. All of that while thinking, "Hm, this laptop might die at any time".

Well, guess what happened

The laptop would turn on, fans full blast, and not even a second later it turns off. No chime or anything. It's possible to hear the hard drive suddenly stopping to spin. Literally the previous day was working all nice, when I took it to a different place (got it into my backpack, all carefully, didn't take any hits or anything but might be related?)

I'll add that I've had this issue happen once before, but trying to boot again did the trick.

What might be the problem? Faulty RAM slot? Logic board? Some contact causing a short? I'd like to have some help and see if I can do something, or it's just dead to this point.

I'm not sure if this has been discussed on another thread already, probably I haven't searched enough. So I'd rather straight up ask here.

Some addicional info:
PB G4 12", DVI (1 GHz). Battery is dead. Tried booting with and without the battery, same result.
Didn't try a PMU reset, but I don't know if can do it with the AC adapter plugged in or not.

Thanks in advance!

 

[AphoticD]

I have seen a similar issue on an iBook G4 which turned out to be a faulty HDD... but before you dig that deep, a simple thing to try according to this KB article is the PMU Reset (applies to all PB G4 12” models);

1. If the computer is on, turn it off.
2. Reset the power manager by simultaneously pressing and then releasing Shift-Control-Option-Power on the keyboard. Do not press the fn (Function) key while using this combination of keystrokes.
3. Wait 5 seconds.
4. Press the Power button to restart the computer.

 

[eyoungren]

OP, what you describe sounds an awful lot like thermal shutdown. Thermal shutdown is when the Mac gets too hot and in order to not fry components, the Mac simply switches off.

But if it were thermal shutdown then it would be happening ALL the time and you say that it's only done this once or twice before. Previously, it's been working.

I suppose it's possible there may be a faulty thermal sensor somewhere but I have no idea how to track that down. Start with the suggested PMU reset and see what happens.

 

[alexra1205]

Probably a stupid question but... Can I do a PMU reset with the AC adapter plugged in? I don't wanna mess up things further so I'd rather ask and be safe.
I just tried without the adapter connected, and still got the same result.

 

[AphoticD]

Probably a stupid question but... Can I do a PMU reset with the AC adapter plugged in? I don't wanna mess up things further so I'd rather ask and be safe.
I just tried without the adapter connected, and still got the same result.

Yes, that is fine.

If no change then I would dismantle and unplug connections of each device from the logic board to eliminate/isolate the fault.

Once you have the top case off, you can simulate a power button press by shorting the two pins in power button connection on the board with a small flat head driver instead of continuously connecting/disconnecting the button.

Note: the PB G4 12” series is generally considered tricky to work on, so if you are not experienced or confident with dismantling laptops then brace/prepare yourself or find an alternative.

Lots of info here: https://forums.macrumors.com/thread...ll-tear-down-ssd-upgrade-and-cpu-fan.2059980/

 

[alexra1205]

So, current state of affairs...
Once I saw your answer, I tried doing a PMU reset, this time with the AC adapter connected. I saw the light on the charger change color (so PMU did reset), but still no change.

So, I prepared myself, and decided to go the disassemble route the following day (so, today). From @/eyoungren's answer, I thought I should try unplugging the hard drive first, maybe that would fix the issue.

Then I grabbed my tools, followed the iFixit's guide, as well as @/AphoticD's post (very useful both! It helped me a lot), and managed to disassemble the laptop until I got the top case off. Never did a disassemble this deep before, but I managed to do it fine.
(As a side note, looks like someone has been here before! And they seemed to have lost one of the keyboard's screws. That's why it was not firmly attatched on a corner. The hard drive has a manufacturing date of April 2005, so that had been replaced at some time, since this is a '03 PB)

I disconnected the hard drive, tried turning on again and.... Same issue. Still fans full rev followed by a shutdown not even a second later.

At this point, I decided not to go any further for now. Further disassembly (like removing the heatsink) would be a first for me, and right now I don't have any replacement paste or pads or whatever this laptop is using. I'm willing to continue if needed but first I'd like to hear from if it's actually worth it or not, or some other possible issues.

I'd like to do an NVRAM reset too, but since it's not booting past the chime I can't do that (unless there's other way... or maybe resetting NVRAM won't do anything of help). I remember changing a bit the temperature settings in G4FanControl the last time this computer was working, maybe there was some corruption while saving data? IDK. Just theorizing at this point.

Also tried removing the RAM on the RAM slot. Still the same.

Any suggestions?

 

[Certificate of Excellence]

Have you tried booting from a OS X dvd? Stick it in, reboot and hold down option. See if the boot selector shows up?

If you have another Mac with firewire, see if you can connect it via target disk mode as an external hard drive.

Both would illustrate that the logic board is generally ok and you could go on to test/repair the hdd in disk utility (either from the functioning Mac or under tools on the OS X dvd.)

Now if you can’t, then I’d yank the hdd out and put it in an enclosure and test it on another Mac - see if it passes a health test in DU.

Without the hard drive in there, you should still get a flashing folder question mark when you try to boot.

If you can get past the freeze, booting into open firmware could give clues as to issues occurring.

Regardless, since you have it apart, I’d repaste/thermal pad the powerbook as what’s on there probably isn’t doing too much and these things run very hot. Be very careful releasing the heatsink mounts. They have a bad habit of breaking off their logic board mounts (repairable but a PITA).

I agree it’s acting a lot like some sort of thermal issue shutting the system down.

 

[AphoticD]

So, current state of affairs...
Once I saw your answer, I tried doing a PMU reset, this time with the AC adapter connected. I saw the light on the charger change color (so PMU did reset), but still no change.

So, I prepared myself, and decided to go the disassemble route the following day (so, today). From @/eyoungren's answer, I thought I should try unplugging the hard drive first, maybe that would fix the issue.

Then I grabbed my tools, followed the iFixit's guide, as well as @/AphoticD's post (very useful both! It helped me a lot), and managed to disassemble the laptop until I got the top case off. Never did a disassemble this deep before, but I managed to do it fine.
(As a side note, looks like someone has been here before! And they seemed to have lost one of the keyboard's screws. That's why it was not firmly attatched on a corner. The hard drive has a manufacturing date of April 2005, so that had been replaced at some time, since this is a '03 PB)

I disconnected the hard drive, tried turning on again and.... Same issue. Still fans full rev followed by a shutdown not even a second later.

At this point, I decided not to go any further for now. Further disassembly (like removing the heatsink) would be a first for me, and right now I don't have any replacement paste or pads or whatever this laptop is using. I'm willing to continue if needed but first I'd like to hear from if it's actually worth it or not, or some other possible issues.

I'd like to do an NVRAM reset too, but since it's not booting past the chime I can't do that (unless there's other way... or maybe resetting NVRAM won't do anything of help). I remember changing a bit the temperature settings in G4FanControl the last time this computer was working, maybe there was some corruption while saving data? IDK. Just theorizing at this point.

Also tried removing the RAM on the RAM slot. Still the same.

Any suggestions?

In my experience, the DC-to-DC daughter board which is in the area under the trackpad are a bit flakey.. follow the ifixit steps to remove this board and then try powering on again - iirc, the heatsink doesn’t need to be removed for this.

I can’t recall if the logic board will POST without the daughter board... but worth trying as I have had two of these burn out in my PB 12’s

 

[alexra1205]

(Edited due to formatting issues)

Have you tried booting from a OS X dvd? Stick it in, reboot and hold down option. See if the boot selector shows up?

The laptop turns off not even a second after pressing the power button. No chime or anything, just fans full speed and then it's off. So I cannot boot anything. This also happens with the hard drive unplugged.

Now if you can’t, then I’d yank the hdd out and put it in an enclosure and test it on another Mac - see if it passes a health test in DU.

So I did this cause it shouldn't be that difficult, I had the tools and went ahead using my MacBook4,1 and a USB adapter for hard drives. Well, I used the verify disk option on Disk Utility and it passed just fine.

(Side note: Seems that the PRAM battery has died recently on the Macbook... Right when I plugged that laptop in, it just booted without pressing the power button. And the date was set incorrectly, and the wifi password was gone too)

Without the hard drive in there, you should still get a flashing folder question mark when you try to boot.

My issue means this won't happen either.

Regardless, since you have it apart, I’d repaste/thermal pad the powerbook as what’s on there probably isn’t doing too much and these things run very hot. Be very careful releasing the heatsink mounts. They have a bad habit of breaking off their logic board mounts (repairable but a PITA).

Hmm... I remember when idle, it was running at about 43 C, and when on load I tried to keep it at 50 C (CPU temps, add a few degrees more for GPU temp, if I recall correctly which was which on G4FanControl). The Macbook runs hotter! But yes, I might repaste or replace the thermal pad if needed.

In my experience, the DC-to-DC daughter board which is in the area under the trackpad are a bit flakey.. follow the ifixit steps to remove this board and then try powering on again - iirc, the heatsink doesn’t need to be removed for this.

I can’t recall if the logic board will POST without the daughter board... but worth trying as I have had two of these burn out in my PB 12’s

Then I resorted to this... I simply unplugged the DC-DC board from the main board (without unplugging anything from the DC-DC board, just for testing). Now, when plugging the AC adapter in, it changes its light to orange (just like it does when there's a battery in), and the computer won't turn on at all.

So, there it is. Maybe this is the normal behaviour, maybe not. I feel like this issue might be too deep for me to fix right now, but I still wanna hear what you all think might be the problem, and maaaybe I'll be able to do something.

 

[Certificate of Excellence]

ok I see - it's immediate. Hmm, I had a 12" powerbook where the GPU failed (due to heat) but it still would allow me to boot up into safe mode and it sounds like you cannot achieve any sort of OF/TDM/SM/Boot select behavior. I had another that would freeze while in the boot screen but that was a faulty airport card - again, was not an immediate on and off issue and was easily fixed after booting into Open firmware and reading the log.

It's beginning to sound more and more like a faulty/temperamental logic board to me or a heat issue. I still think it makes sense to replace the thermal paste and pads on the cpu and gpu (I mean what do you have to lose at this point). That sort of immediate on and off + ramped up fans is indicative of overheating; the thing's trying to save itself before it fries completely.

 

[alexra1205]

Ahh... Then it'll be a project for another time. I'm working on other projects right now.

I don't have many hopes on this, and I'm already thinking which is going to be my next PPC Mac. Hoping to find a DLSD for that.

Anyway, thanks to everyone! Expect some more posts here once I get to it again...