iBook G4 freezing, and nothing much more

I’m hoping for some creative help with a very troubling problem I’m having with my G4 iBook.

Bought in 2004, this 14-inch iBook is running Tiger (though it came with Panther) and has 768 MB of RAM, a 60 gig hard drive, and a 1.07 GHz processor. It has never caused me any problems and I have been able to run an impressive array of programs at the same time with only about a dozen full-scale crashes that I can recall.

About three weeks ago, the computer started to freeze repeatedly, particularly when hooked up to an external monitor or TV. I ran the Disk Utility, both from the computer and off the Mac Os install disk, though no problems were found. The freezing continued and became even more persistent. At that time, programs would become non-responsive, the clock would stop, but the mouse pointer could still be moved. Sometimes, a thin line of zebra stripes would appear at the top of the screen and the mouse pointer would not move. A small, multi-coloured line (about one pixel wide and barely the height of the top menu bar) developed on the screen and has remained since.

Luckily, I use the computer for work and sent it off to our company repairperson, who specializes in Macs. As always seems to be the way, he could find nothing wrong with the computer — it worked fine for him over the three days he tested it. He installed a fresh copy of Tiger, removed Norton Utilities, which often can often cause operating problems, according to him. (He did not remove any other programs.) He did a hardware diagnosis and found no problems. He sent it back to me.

When I got the computer back, at first it worked fine. The only problem was that a blue screen would appear and the computer would become unresponsive when I hooked it up on the fly to an external monitor. (The computer tech suggested I hook up the source before powering the computer on to avoid a crash, though this was unnecessary before).

I moved my preferences from the archived system folder to the new library folder. The freezing then returned. This time, much worse. Without going into detail at this point about the freezing, I can say that the freezing became so bad that I decided to do something drastic — wipe the hard drive and re-install Tiger completely, which I did. (I backed up all my documents and preferences on another hard drive, of course.) This seemed like a good thing to do, seeing as the problem may have been with one or more of my programs. I was getting some corrupted file messages before I wiped the hard drive.

Sadly, even after two reinstalls of Tiger, freezes are persistent. I have also reset the power management unit several times, along with resetting the Parameter RAM. I have also turned off hard disk spin down and the option that puts the computer to sleep (in the Energy Saver control panel) to avoid unnecessary sleeping. No luck — freezes continue.

At this point, the computer has a clean hard drive and fresh copy of Tiger, including all the software updates through the Apple menu. I do have a few basic programs installed, such as Microsoft Office, iPhoto and some small, free downloadable programs. There is about 41 gigs of free hard disk space.

Here are the freeze patterns:

- When the computer freezes, the seconds counter on the clock stops, all programs are unresponsive and no force quitting is possible. The pointer can still be moved by the mouse, but that is the only action the computer makes. The only way to reset the computer is to hold down the power button.
- Typically, if the computer is powered back on within less than five minutes, it boots up past the Apple symbol and spinning dial, then freezes on the blue screen.
- If I wait for about five minutes or more, the computer will almost always boot up normally.
- The computer seems particularly susceptible when peripheral devices are attached while running. For instance, it has crashed a few times while the computer was running as soon as — or shortly after — I inserted a USB key, a firewire cable (for a firewire transfer), or unplugged and re-plugged in the power adapter.
- It has also taken to freezing or crashing when audio or video is played — iTunes, DVD Player (especially) or Quicktime. It doesn’t always freeze or crash, but it more often does than does not. It has crashed a few times when Acquisition — a peer-to-peer file sharing program — was running. I am currently running the Internet through an Airport wireless connection.
- The computer was freezing consistently today after about 45 minutes operation, even with no programs running. I reset the Power Management Unit, Parameter RAM and disabled sleep and hard disk spin down, and it ran for two hours this evening (with no programs running and no network connected) and did not freeze. I intend to try a longer run overnight to see how it fairs.

Sorry for the long description. I just want to be very thorough with my explanation so potential problem solvers have enough to go on.

Hope you can help! I really appreciate it. I love this computer and am not quite ready (financially) to buy a new one.

- niall

14" iBook G4, 768 RAM, Mac OS X (10.4.8), Processor: 1.07 GHz, HD: 60 gig, Airport Extreme installed

Posted on Feb 2, 2007 10:27 PM

Reply
21 replies

Feb 5, 2007 12:55 AM in response to Boece

I ran a couple of interesting tests tonight which I'd like to share the results from:
- I downloaded a CPU temperature widget and monitored that against use of applications. I loaded up the computer with a bunch of running programs and intense processes. At 49.5 degrees celcius, it crashed. Not froze, crashed - absolutely no response, looping of whatever sound was playing, a thin band of zebra stripes on the top.
- Re-booting was not successful right away, as usual. (Usually, it needs 5 to 10 minutes before a successful re-boot.) But by cooling the iBook down in the fridge for one minute, it DID re-boot. All this suggests to me that the running temperature of the iBook is a key part of its malfunction, though not the only part.
- While trying to duplicate the above test, it became apparent there are other uses of the CPU that cause freezing. While plugging in the power adapter, it made its little sparking sound. This caused a freeze. Running the DVD player with other programs running also caused a freeze. In both these last cases, the temperature was about 44 C.

I wonder if the real culprit is to do with some sort of CPU or temperature management thing that a) will not let the computer operate at high heat (though 49 C is not too high - I recall it getting up to 60 C and running fine); and b) does not like complex processes, such as the DVD drive and some peripherals.

Perhaps the fan system shorted out when the plug came out of the wall. Although the computer clearly has some cooling capacity if the temperature it staying relatively low. Plus, high temperature is not the only cause of freezing.

Any thoughts?

Feb 5, 2007 11:05 AM in response to Niall Mckenna

Well, I don't know about the repair. Show your computer guy a print out of this thread.

It's encouraging that he had no problems over the course of three days when using a different power adapter. That's our best hope for a cheap fix.

If it really is a logic board problem, most front-line computer guys just swap the board, and the old one goes who knows where to people who actually can fix the boards. Which means you have to pay for a replacement logic board, which I suspect isn't cheap.

Depending on how good your computer guy is with a soldering iron, there may be some obvious broken solder joint where a peripheral connects that he can fix.

Or he might spot a capacitor that is bulging that he can fix.

But as I say, typically repairs on logic boards are made by buying a "new" one. (The "new" one is actually someone else's old one that has been repaired.)

Feb 6, 2007 4:17 PM in response to Boece

I've forwarded this posting off to the computer tech for my work.

I had a chat with a local computer tech today. He said iBooks have heat problems, caused primarily by poorly applied heat paste on the heatsink in the CPU (applied in the manufacturing process). Essentially, the amount of heat paste is so much, according to him, that it eventually starts to conduct heat, instead of dissipating it. This causes the iBook to overheat and the CPU to crash in order to protect itself. He said the solution would be to remove the existing heat paste with isopropyl alcohol, then apply new paste. I'm going to make this suggestion to whoever fixes my computer next and see if it does the trick.

Have anyone ever encountered this problem (and solution) before?

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iBook G4 freezing, and nothing much more

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