11 Replies Latest reply: Aug 28, 2013 10:13 PM by Knucklesmac
Djipson5 Level 1 (0 points)

Hello everybody,



My PowerBook G4 1,67Ghz has been fine for a couple of time. But today it started to freeze. When it freezes the mouse doesn't move and all the computer stop working. I need to press power button for a long time. I reinstalled it, tried new RAM Sticks but nothing changed. I can turn it on and work for 15min then it freezes totally. The optical drive is dead so I can't try a AHT. The computer isn't slow or anything else. The only issue is the fact that it freezes. Maybe a motherboard issue ?

  • Knucklesmac Level 4 (2,225 points)

    Hello and welcome to the support community


    Well there is a number if issues it could be.

    What springs to mind and that would be a failing hard drive or the common memory problem.


    If you have a Mac OS X restore disk (came with your powerbook) try booting from that.

    From the install menu, select utility  and disk utilities.

    Run a check on your hard disk to see if there are any errors.

    If there is, you will need to replace your hard drive.


    If all is well with your hard drive.

    Try removing one of your memory modules in turn.

    Power on the unit each time to see if it freezes.

    If it doesn't freeze with just one memory say in slot one, then you can point the problem at the memory slot two, or vice versa.

  • Djipson5 Level 1 (0 points)

    Hello and thank you.


    I've tried with 4 RAM sticks separatly but it still freezes. I tested the Hard drive and it told me "Macintosh HD seems to be ok". I have another PowerBook, so I tried there the RAM and Hard Drive and they are just doing fine on it but once I bring them back into the actual powerbook, it starts freezing once again. Really frustating. Can it be a problem with the RAM Slot ?

  • dalstott Level 4 (2,625 points)

    Have you tried things like a safe boot, PMU and PRAM reset? Or possible have DiskWarrior to run?  If not these links may help.










  • Djipson5 Level 1 (0 points)

    The hard drive has been erased, so I don't think I can go in Safe Mode. Right now I got another problem, as soon as it reatches the installation menu, the screnn goes black.

  • Knucklesmac Level 4 (2,225 points)

    Sounds like the problem I had with the exact same model.

    My PowerBook 1.67Ghz was working fun one day and then started to freeze. The unit would then show a black screen which you could see the desktop in the background which was very faint.


    The problem turned about to be temperature. Took me a while to investigate the problem.

    What happened to mine, was something you can't spot With ease. The processes and graphic processor was not getting the efficacy from its heat sink, due to it being warped over time.

    I took the unit apart and fixed the heat sink, so the the GPU and CPU would make better contract with it. Applying thin compound paste.

    Never had a problem with the PowerBook after doing this.

    Have even kept an eye on the temperature  using istat. Seems to run fine now.


    What I believed happened, was the temperature was getting too hot quickly. With no help from the heat sink dissipating the heat, the PowerBook become unresponsive.

    The only way to reboot the machine was to power down. Don't help the hard drive and soon it would fail if I kept doing so. Even tried reinstalling Mac OS X from disk and that would stop half way through (soon as the temperature  got hot)

    Ever since I fixed the heat sink issue, it reinstalled fine and has worked since.


    Think this could be a common problem with this model of PowerBook.

  • Djipson5 Level 1 (0 points)

    Hello, and thank you very much. Yes in fact we have the same problem. But please can you give me more infos on how to solve it. Where can I locate the Heat Sink ? And what should I do ?

  • Knucklesmac Level 4 (2,225 points)



    http://www.ifixit.com/Guide/Replacing+PowerBook+G4+Aluminum+15-Inch+1.67+GHz+Hea t+Sink+%26+Fans/654/1


    This link provide you with how to remove and where the heat sink is located.

    I removed mine and used a level to make sure the surface was flat. Removed the old heat sink compound and put new compound on. For mine, Apple had put loads of compound on, which over time become sticky and thick.

    Too much compound will provent the heat sink from being effective.


    The idea is for the CPU and GPU to touch the metal of the heat sink, allowing the heat to dissipate though the heat sink.

    Which is attached to the base. (That's why the base get so hot)


    Just for clarification, I recently tested this therory of a heat problem, by simulating a blockading in effective cooling.

    I placed the PowerBook on a thick carpet and covered the vents. Sure enough after a while started to freeze and the screen when black. So I know this was a problem with the effective cooling.


    It could also be a defective tempature sensor, preventing the fans from coming on before it gets too hot.

    That problem I've had in the past with a 17" PowerBook.


    There are six sensors on these PowerBooks.

    Some can be replaced, others can't.

    The CPU sensor is part of the CPU and can't be replaced, unlike the tracker pad sensor which can be if replaced the tracker pad.

  • Djipson5 Level 1 (0 points)

    Well, this is my second heat issue. Before the sensor under the trackpad was submitting bas informations so the computer went to sleep everytime I used it. I removed this sensor and the computer got fine. And today it's a heat sink issue. I do own a MacBook Pro 2011 but I l like using my PowerBook. Tomorrow I'll move to the shop to buy compound paste. Thank you very much for this trick, I could have been looking for a solution for months. Cheers.

  • Knucklesmac Level 4 (2,225 points)

    You're welcome.


    What I done with mine is place a paper thin peace of metal between the heat sink and GPU.

    That way I could guarantee it was touching. It gave millimeter thickness shim. You can get a sheet of metal like this from craft shops. Just cut it to the size of the GPU seat on the heat sink.

    Put a tiny amount of compound on the processors seats and assemble.


    I believe the 1.67Ghz processor in these PowerBooks are running far too hot for the design.

    It's cooling is a little insufficient in my opinion. My MacBook Pro doesn't burn my knees when it on my lap, unlike my trusted PowerBook, that runs around 50-90 degrees.  Same cooling structure as the 1Ghz model. Which would have been fine for that running a lower temperatures.

    Like you, I enjoy using my PowerBook.


    Best of luck.

  • Djipson5 Level 1 (0 points)

    Hi there!!!!!

    I've applied the compound and I have been using the PowerBook all day long and everything's still fine. It's probably an issue with 1,67Ghz models. I have another PowerBook 15" 1,5Ghz and it has never had any heat issue. So far, thank you.  Let's enjoy these old G4 Mac ;-)

  • Knucklesmac Level 4 (2,225 points)



    Mine was fine until yesterday. The base got really hot and then it froze again.

    It's come to my attention, that the fans are not coming on.

    The CPU temperature reached 83 degrees and only the left fan cut in for a short while running at only 67RPMs.


    I'm starting to believe my heat issue doesn't just stop at poor heat dissipation, but maybe a sensor (logic board ) problem. Hopefully yours haven't the same problem and your fans are coming on when required.


    Apple hardware test passed the fans as working, I could hear them working.

    Yet when the PowerBook gets hot, they don't seem to come on. That has to be a sensor problem. All of which are controlled by the logic board.


    Like you, my 1.5Ghz PowerBook works fine. So I'm lead to believe this could be a common problem with the

    1.67Ghz model.