Invalid memory access

My Powerbook G4 has recently been experiencing huge problems. It can only occasionally start up in normal mode - I get the normal grey start up screen, then either a blank blue screen with no cursor, or another grey screen with 4 or 5 lines all across it, or if I'm lucky, a proper start up.

I've been able to start up in Safe Mode.
I've fixed all permissions.
I've verified the harddrive (no fixes needed).
I've zapped the PRAM.
I've done the fsck thing (no fixes needed).

The big problem is that I'm currently traveling and I don't have my install CD/DVDs with me. I did download a copy of the hardware test and burned it to make a AHT start up CD. When I run this, I get:

invalid memory access at %SRR0: 00032ed8 %SS1: 003030

and then it gives me the option to 'mac-boot' or 'shut-down'. The weird part is that the AHT readme mentions a control panel of some sort when the AHT runs, but all it get is white text on a blank screen, kind of like a terminal prompt. Is that what I'm supposed to get?

I've tried pulling out the 3rd party RAM I installed, but even with just the internal RAM, the AHT gives me the same invalid memory access message.

Any help would be greatly appreciated.

Does your macbook make sounds when you start up?

If it beeps, it could mean you have faulty (internal) RAM

Apparently it may be a fault with the test software, not the RAM

What version of OS X are you running on the G4

RobbertV, it only make the normal start up chime (or dong, or whatever). No extra beeps.

Louishen, I'm running 10.4.11. I got the test software from the apple site, here:

Apple Hardware Test Images

As an update, I've booted-up in Open Firmware and reset the NVRAM, but unfortunately it didn't seem to resolve the issue. It still won't boot most of the time.

Incidentally, I have begun to identify a pattern on the occasions when it does boot up properly. The machine will force quit certain programs that use video as soon as I open them. VLC media player closes as soon as I open it, and iTunes will close when I try to access any videos. Strangely, iTunes will also quit if I try to change the view to CoverView. (Incidentally, quicktime runs without a problem, although it seems to drop frames, ie the playback is a bit chunky.) Also, the machine will crash (greyed out screen with the 'you need to restart your mac' message in four languages) when, in Finder, I have it set to column view and I highlight a video file, thereby creating a 'preview' of the video in the rightmost column. When I do this, bang!, the entire machine revolts and I'm told to restart.

I don't know if any of this means anything, but I thought I'd mention it.

Any ideas?

good outcome

After sending the machine away in Thailand, and two weeks of waiting, it looks like good news all around. The guys in Bangkok were able to get things sorted -- while there was a bit of a language barrier, as best as I can understand there explanation, it seems that the 'circuit' on the graphics card needed to be taken out and either cleaned or replaced, the technician used both terms during his review of what was done.

To any of the more technically inclined out there, does this make sense?

But the important thing is that the laptop seems to be in perfect working order now. VLC works as well. No data or applications were lost in the process, and in the end it only cost about $100. Plus, the work has a two month warranty, which is a nice touch, even if I won't be in the country to take advantage should I need to. All in all, lovely.

As a final (hopefully) update, the problems I was having with my G4 failing to start-up normally began to recur about two months after I had it serviced at a Mac retailer in Bangkok. I was able to get things started in Safe Mode, which worked well for the next few months, but a few weeks ago, Safe Mode crashed as well, and everything I tried (with the exception of Single User Mode) resulted in a grey screen with horizontal lines across it (seemingly an indication of a hardware problem).

Well, after a bit of nosing around on the internet and in a few other forums, I can across the keen idea of going into Single User Mode and removing video-related kext files from the systems/library/extensions folder (very dangerous stuff, I know), sort of like what I was trying to do with the booting the audio kexts to get sound running in safemode (as discussed earlier in this forum). I did this one at a time, to see if I could find out what might be causing the problem. First I discovered the importance of the NVDANV30Hal.kext file (removing it stopped the start up process entirely for normal and safe mode).

Then I made the critical discovery. By removing the NVDAResman.kext file from the extensions folder, my machine is now miraculously able to start up in normal mode with no noticeable side effects except for an inability for the machine to be put to sleep. If it's between a completely non-functional machine, and one that can't sleep, I'll take the latter.

Hopefully this little discovery might be able to help others in a similar situation (video hardware crash on startup).

Also, if any of you know any define known problems that will come about from yanking the Resman kext, I'd love to be properly warned ?

thanks much,
tim