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PowerPcboi

macrumors newbie
Original poster
Feb 21, 2020
28
9
If things are getting that hot it seems you should be seeing some fan activity.

Have to tried resetting the PMU?

Also, while you have the thing apart, you may want to check for voltage to the fan, and make sure it's just not a dead fan.
I have a multi meter, were are the fan connections that I should check? Also how would I reset the PMU, I have heard of this but I have never attempted it.
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I was going to suggest that, but we don't know if the CPU definitely uses thermal pads to justify that.

And either way, if the CPU was indeed shipped with a thermal pad, I'd rather replace it with a new pad than risk doing any damage to the CPU with a slightly too thick or slightly too thin shim pasted to both sides.

...But, you know, IMO.
z970mp

Just a update on the thermal pads, I did get new thermal pads, and for all the iBook users, yes the ibook G3 models use thermal pads. I believe because the thermal paste can not fully contact the heat sink and that is why.

The new pads made a huge difference. As a test I ran Cine bench(2003) before the new pads, and it froze after 3 seconds. With the new pads it completed the test, although just barely. Still no fan activity.
 
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z970

macrumors 68040
Jun 2, 2017
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Still no fan activity.

After all of that, it's likely the fan is faulty. It's there to cool down the heatsink, and if it's not doing its job, then there's a problem.

See if you can track down another one from eBay. Getting its model number may be helpful with this.
 
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PowerPcboi

macrumors newbie
Original poster
Feb 21, 2020
28
9
After all of that, it's likely the fan is faulty. It's there to cool down the heatsink, and if it's not doing its job, then there's a problem.

See if you can track down another one from eBay. Getting its model number may be helpful with this.
I found this fan. Hopefully I am not about to get ripped off! I think the fan is the problem. I will find out soon.
 
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sparty411

macrumors 6502a
Nov 13, 2018
553
501
Idk if this is helpful at all, but in my experience, random freezes / lockups on iBook G3's is due to a failing Mobility Radeon 7500 chip, which is EXTREMELY common(I believe upwards of 50% of iBook G3's had this problem). I never even heard the fan on my iBook G3 kick on (Apples notoriously passive fan curves *cough* *cough*), until I installed Linux on it tbqh, so the fact that it isn't spinning up doesn't mean much IMHO. I hope I'm wrong about the GPU, but I'd put a lot of money on it being the culprit.
 
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AphoticD

macrumors 68020
Feb 17, 2017
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@sparty411 that was definitely the case with the Radeon 7500 models, but I believe the OP has the earlier Rage 128 powered iBook, which I have not seen with a GPU failure.

I was tinkering with my PBG4 12” the other night and found the fan controls in Open Firmware for setting fan on/off and manually reading and writing the fan speed.


This got me wondering if I could ramp up the fan on the iBook G3 manually using OF - even just to test if the fan can spin. But unfortunately I can’t find anything fan related in OF on this model. Someone with more OF experience may know how to locate the device?
 
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z970

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Jun 2, 2017
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I was tinkering with my PBG4 12” the other night and found the fan controls in Open Firmware for setting fan on/off and manually reading and writing the fan speed.

http://macos9lives.com/smforum/index.php?topic=4867.0
This got me wondering if I could ramp up the fan on the iBook G3 manually using OF - even just to test if the fan can spin. But unfortunately I can’t find anything fan related in OF on this model. Someone with more OF experience may know how to locate the device?

This is why we need a populated Open Firmware Wiki. The subject is a gold mine just waiting to be dug out.
 

DearthnVader

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Dec 17, 2015
2,207
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Red Springs, NC
@sparty411 that was definitely the case with the Radeon 7500 models, but I believe the OP has the earlier Rage 128 powered iBook, which I have not seen with a GPU failure.

I was tinkering with my PBG4 12” the other night and found the fan controls in Open Firmware for setting fan on/off and manually reading and writing the fan speed.


This got me wondering if I could ramp up the fan on the iBook G3 manually using OF - even just to test if the fan can spin. But unfortunately I can’t find anything fan related in OF on this model. Someone with more OF experience may know how to locate the device?
Ask Daniel over there at OS9 Lives, he is our resident Open Firmware guru.......
 
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sparty411

macrumors 6502a
Nov 13, 2018
553
501
@sparty411 that was definitely the case with the Radeon 7500 models, but I believe the OP has the earlier Rage 128 powered iBook, which I have not seen with a GPU failure.

I was tinkering with my PBG4 12” the other night and found the fan controls in Open Firmware for setting fan on/off and manually reading and writing the fan speed.


This got me wondering if I could ramp up the fan on the iBook G3 manually using OF - even just to test if the fan can spin. But unfortunately I can’t find anything fan related in OF on this model. Someone with more OF experience may know how to locate the device?
I own a 500 MHz iBook G3 with a dead Rage 128 :(
 
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PowerPcboi

macrumors newbie
Original poster
Feb 21, 2020
28
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I own a 500 MHz iBook G3 with a dead Rage 128 :(
I am sorry you rage 128 chip died, that is really disappointing. The truth is all the GPUs on a old computer have a chance of death. I mean they are built really well but it can happen. These iBooks are 20 years old on some models! It is crazy to think about how they have got this far. also yes my iBook has the rage 128
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@sparty411 that was definitely the case with the Radeon 7500 models, but I believe the OP has the earlier Rage 128 powered iBook, which I have not seen with a GPU failure.

I was tinkering with my PBG4 12” the other night and found the fan controls in Open Firmware for setting fan on/off and manually reading and writing the fan speed.


This got me wondering if I could ramp up the fan on the iBook G3 manually using OF - even just to test if the fan can spin. But unfortunately I can’t find anything fan related in OF on this model. Someone with more OF experience may know how to locate the device?
Very interesting. I am surprised that Mac Rumors dos not have a open firmware section. I have used it some and there are tons of useful commands. It is great for troubleshooting as well.
 
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z970

macrumors 68040
Jun 2, 2017
3,589
4,541
I am surprised that Mac Rumors dos not have a open firmware section. I have used it some and there are tons of useful commands. It is great for troubleshooting as well.

Now we do. Albeit, one under construction, as I just do not have the time to dedicate to it.

 

PowerPcboi

macrumors newbie
Original poster
Feb 21, 2020
28
9
I tried the new fan, and well it did not work🤔. Something must be seriously messed up. As we have tried everything I am not sure were to continue, I will keep a eye on this thread but I believe there is not more route to take after this. Also I noticed that my mac is missing screws, not sure if that has anything to do with it. Otherwise, I believe this is the end of the line. Thanks to all those who helped, if anyone thinks of anything else, let me know.
 

z970

macrumors 68040
Jun 2, 2017
3,589
4,541
Have you ever tried another OS? Maybe one of the thermal management kexts in your current install has gone missing for whatever reason. Otherwise, it sounds like the logic board connector is bad.

Perhaps one of the fan's electrical paths on the PCB has been severed in some way? If you were really dedicated, you could dismantle everything and inspect the connector's path along the board, how it travels and where it originates. If that's the case, you could even repair this theoretical problem area with one of those board electrical path repair tool things - just be VERY careful you paint over the right place...

Hey, it beats chucking the 95% functional rest of the board!
 

spyguy10709

macrumors 65816
Apr 5, 2010
1,008
673
One Infinite Loop, Cupertino CA
I tried the new fan, and well it did not work🤔. Something must be seriously messed up. As we have tried everything I am not sure were to continue, I will keep a eye on this thread but I believe there is not more route to take after this. Also I noticed that my mac is missing screws, not sure if that has anything to do with it. Otherwise, I believe this is the end of the line. Thanks to all those who helped, if anyone thinks of anything else, let me know.
Did you ever get around to that PMU reset? If not, https://lowendmac.com/2018/pram-and-battery-issues-in-ibooks-and-12-powerbooks/ is a great explainer.

In short -

  1. Reset the PMU. There is a small reset button “under the grille”. Straighten out the end of a paperclip and hold the reset button down for 5-10 seconds.
    1. Addendum from old apple docs -
      1. For iBook (16 VRAM) and later models of iBook, there is no physical reset button.

        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 iBook computer.
  2. Reset the PRAM and/or NVRAM (nonvolatile RAM). Shut down your ‘Book, start it up, and hold down Cmd-Opt-P-R simultaneously until it chimes 3 or 4 times to clear out the old PRAM data.
 
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PowerPcboi

macrumors newbie
Original poster
Feb 21, 2020
28
9
Did you ever get around to that PMU reset? If not, https://lowendmac.com/2018/pram-and-battery-issues-in-ibooks-and-12-powerbooks/ is a great explainer.

In short -

  1. Reset the PMU. There is a small reset button “under the grille”. Straighten out the end of a paperclip and hold the reset button down for 5-10 seconds.
    1. Addendum from old apple docs -
      1. For iBook (16 VRAM) and later models of iBook, there is no physical reset button.

        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 iBook computer.
  2. Reset the PRAM and/or NVRAM (nonvolatile RAM). Shut down your ‘Book, start it up, and hold down Cmd-Opt-P-R simultaneously until it chimes 3 or 4 times to clear out the old PRAM data.
What does under the grille refer to?
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Have you ever tried another OS? Maybe one of the thermal management kexts in your current install has gone missing for whatever reason. Otherwise, it sounds like the logic board connector is bad.

Perhaps one of the fan's electrical paths on the PCB has been severed in some way? If you were really dedicated, you could dismantle everything and inspect the connector's path along the board, how it travels and where it originates. If that's the case, you could even repair this theoretical problem area with one of those board electrical path repair tool things - just be VERY careful you paint over the right place...

Hey, it beats chucking the 95% functional rest of the board!
I think I am going to take a shot at the recently reappearing MintPPC Linux and put the thing back together.
 
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