Mac freezes and need to be restarted

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.

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

http://support.apple.com/kb/ht1564

http://support.apple.com/kb/ht1455

http://reviews.cnet.com/8301-13727_7-10330118-263.html

http://support.apple.com/kb/HT1431

http://support.apple.com/kb/HT1379

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.

Hello,

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.

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.

Fantastic!

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.