Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

Resetting SMU PRAM & NVRAM iMac G4 Flat Pannel

I posted another ? in a different forum but have not received any help so far. I've been reading about different potential 'fixes' to issues which I seem to be having with my iMac G4 Flat Pannel.

Some background info:

My computer froze up and I could not get it to respond with keyboard commands and it would not restart or shut down when I held the back button down either. I decided to cut the power on the power strip, and when I restarted my computer, I heard the fan come on, but my screen was completely black. There was no 'power on' light on the monitor this time either and the computer no longer responds to the keyboard and my mouse no longer lights up..

I'm hoping someone can help with some questions I have after having read about resetting various buttons..


First, will resetting the PRAM result in loss of any data on my computer?

Second, do G4 iMacs have a SMU reset button, or is this only on G5 models?

Third, will resetting the NVRAM result in a loss of my data?

Lastly, does anyone else have any suggestions to help fix my problem; does it look like my computer is dead?

Thank you for any help! =) *april

iMac 15" Flat Pannel 700 MHz PowerPC G4 1GB SDRAM, Mac OS X (10.3.x), i love my little bubble computer

Posted on Mar 25, 2008 9:41 AM

Reply
Question marked as Best reply

Posted on Mar 25, 2008 10:15 AM

Well, if you did a search in Apple's Support before posting you would have fund this for PRAM:
http://docs.info.apple.com/article.html?artnum=2238
and that it's call SMU on newer models, but PMU on older ones:
http://docs.info.apple.com/article.html?artnum=95165
20 replies

Mar 25, 2008 11:30 AM in response to SmartMarc

Halo Marc,

Thank you for responding.. I did in fact do a search and I read the two documents you referred to among several other documents. After reading all of them, I was a little confused which is why I asked for further help. I do not feel those documents or the others I read fully explained all of my questions, and I felt it better to ask instead of furthering my problems..

I went ahead and reset the PMU; there is still no change. I am unable to follow the other reset instructions (Command, Option, P, and R) in the other document because my computer no longer recognizes my keyboard etc.

Mar 25, 2008 11:54 AM in response to Goonie Girl =)

Ok, resetting the PMU is the last resort. If that doesn't bring your Mac back to life there's something seriously wrong.
If really nothing happens when you power it up, you will not even have a chance to boot into the Hardware-Test CD/DVD that came with your Mac.
Did you install more RAM? If yes, remove it and try again.
If not you can't do anything more and have to take it to an authorized Service Provider.

Mar 26, 2008 3:10 PM in response to SmartMarc

Guess I never thought of RAM being able to die before.

Do you know if that would make my screen and keyboard go dead like they did, Marc? I had several, 'memory almost full' warnings before my iMac froze and stoped responding. Would it be possible for the 1 GB of SDRAM to die all at once and if that was possible, there would probably be no way for me to retrieve the data that was stored on my computer right?

Mar 27, 2008 2:11 AM in response to Goonie Girl =)

Defective RAM can cause the strangest problems - Your computer has two RAM chips (or SO-DIMMs as I should call them). It's enough that one of them starts to act funny. Unplug everything, open the service hatch and remove the DIMM you see right there. Close the hatch and start you computer.
If that didn't help it could still be the other DIMM that is flacky, but that one is buried inside of your computer and not easily replaceable.

Mar 27, 2008 12:27 PM in response to SmartMarc

Hallo Marc,

I just removed the SO-DIMM chip under the hatch as you suggested and powered back up.. still nothing new however. Don't know what else I could do myself.

I'll make sure to tell the Tech that the issue might be with the interior DIMM. I probably shouldn't try to mess with the interior one.

I'm mostly hoping I'll be able to access my iTunes library again.. I'm wondering if you would know, if I do have to buy another computer and I re-use my old DIMM from this computer (If they're fine), is my iTunes library stored on them and if I put them in my new computer, will those files be on my new computer? Sorry if this is a stupid question, I just don't know and wasn't able to find an answer to this question.

Thank you for all your help; I really appreciate it.

Mar 27, 2008 3:04 PM in response to Goonie Girl =)

I don't think you have to worry too much about your files, your hard disk should be ok, although I can't say for sure from here. If you have to buy a new computer ask the technician to extract the hard disk from the old iMac. You can then decide if you want to use that one in an external casing and use the migration assistant to restore the files to your new system - and maybe keep the external one for backup purposes 😉

Apr 1, 2008 6:24 AM in response to Goonie Girl =)

Goonie Girl =) wrote:
I had several, 'memory almost full' warnings before my iMac froze and stoped responding.


My hunch from that comment would be that you have filled the hard disk up. Even with just 15% free you could see a severe degradation in performance and if it fills entirely you could be unable to boot. Can you boot from the OS X install disc?

mrtotes

Apr 1, 2008 10:14 AM in response to mrtotes

Cor blimey, it's mrtotes =) ..thank you for responding!

I am, very unfortunately, unable to boot from the OS X install discs. When I boot up my iMac, nothing happens except I hear the fan go on. My computer's screen is blank and my computer won't recognize my mouse or keyboard either so I can't even eject the CD that is already stuck inside of it either. I don't see any images when I shine a flashlight on the screen; nor does the little 'power on' light come on the screen when I press the power button.

I know I should have emptied the trash before I started to import another cd into iTunes, but I procrastinated because I was in the middle of adding to and backing up my iTunes library. I noticed, when trying to burn a CD, I got an error message and it would not let me burn the CD so I decided to import another CD while I tried to figure out what that first warning message meant. While I was importing the CD, all open programs and my screen froze. After that, I couldn't get my computer to respond to anything. I tried to force quit iTunes etc, but it wouldn't force quit or respond to any mouse or keyboard commands. I then tried to force shut down my computer by pushing the power button in back.. still no go. So then I cut the power on the power strip; when I rebooted, nothing happened except I could hear the fan go on.

I know I did something very bad and my poor computer is punishing me. I I deserve it! I think you are correct about my filling the hard disk up, mrtotes. I was getting warning messages about it for quite some time which is why I was backing up my iTunes library in the first place. I wanted to back them up so I could delete more files afterwards.

Is there anything I can do to fix the issue even if I can not boot from the OS X install disc? Any way to free up memory by doing something with the hardware under the dome? I've already reset the PMU which did not help. I've also removed the user accessable SO-DIMM to see if that would make any difference.. still no change. I just ordered some Silver Themal Paste so I could replace the RAM inside of the computer and be able to seal it correctly. I'll try anything! =)

Apr 2, 2008 7:56 AM in response to Goonie Girl =)

Goonie Girl =) wrote:
I don't have an external firewire hard drive; should I buy one? And if so, might you have any suggestions about which one to purchase? I was also wondering, would any software have to be installed beforehand for it to work?

Do you think it would help if I opened the computer up and got the 'stuck' CD out manualy? Curious.


Could you try removing the disc using the Open Firmware method first please:
  • Switch on
  • After the startup chime, press and hold the keys <command/apple> <alt/option> <o> and <f> ( ⌥ ⌘ F O )
  • At the command line prompt, type: eject cd
  • Hit Return, the optical drive will then open.
  • Remove the disc.
  • Type: mac-boot
  • Hit return.

Hope that works.

mrtotes

Resetting SMU PRAM & NVRAM iMac G4 Flat Pannel

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple ID.