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fusionexr · Mar 31, 2006, 01:19 AM

Hey guys,

This is my first post here. I picked up today from a friend an old 400 mhz graphite imac. I am having a bit of trouble wiht it. I swapped out hard drives at his place from another imac that I had, and booted it up and it booted up perfectly. Now that I am home, whenever I go to power it up the green light turns on, the hard drive spins then it sounds like everything shuts off and the green light dims a bit. No moniter or anything, just silence. What could cause this? Any ideas of what I can do to fix it? Thanks a lot.

fusionexr · Mar 31, 2006, 01:36 AM

A quick add-on. Whenever I hold the shift key, or the space bar instead of the green light dimming the entire computer goes off.... This mac is also running the latest version of OS X 10.3.9 I think. Any ideas? I would like to get this computer up and running agian...

JKT · Mar 31, 2006, 08:48 AM

Check the RAM is seated correctly.

You may need to take it apart again to check your connections for the hard disk are seated properly too.

D'Espice · Mar 31, 2006, 08:49 AM

Have you updated the firmware before booting OS X for the first time? Cause if you didn't, you probably killed it.

vmarks · Mar 31, 2006, 09:05 AM

Booting OS X without having had the firmware updated doesn't actually kill the machine, but it does make life difficult. The best thing to do is find an OS 9 hard drive, install that and boot from it, and then update the firmware.

THEN you can go back to running OS X. I've recovered more than one machine this way.

fusionexr · Mar 31, 2006, 03:35 PM

I actually took the entire thing apart last night and checked every connection there was, everything is connected properly, ram is seated correctly, I tried both ram slots even. No I did not upgrade firmwares before bootingup to my OS X harddrive, but that really seems silly that it can mess with it that badly? I mean it ran perfectly after I booted it up the first time. I will try loading OS 9 back on to it to see what happens. My buddy has the old hard drive that has OS 9 still on it, so I will get it form him and see what I can do with it. Any other suggestions between now and then?? Thanks much

fusionexr · 04:11 PM

Ok so I just tried booting from an OS9 CD and it sounds like it wants to go but then the whole machine just conks out. I am going to get that harddrive tomorrow we'll see whta happens.

EDIT: OK so I found an old hard drive laying around from one of my older macs that had OS9 on it, and I am still gettting the samething when I try to boot it up. It will spin everything, the hard drive, the OS 9 CD that's now stuck in there, and everything except the moniter and then it just dies after about 5 or 6 seconds. I guess something must have fried the way it's acting. Is there any hope for this poor machine? Thanks again

JKT · 05:52 PM

You may want to try replacing the PRAM battery but try resetting the power management unit first (I'm afraid it means taking the iMac apart again). There is a little button on the motherboard:

Quote from the iMac Service Manual:

The PMU Chip

The PMU (Power Management Unit) is a microcontroller chip that controls all power functions for the computer. The PMU is a computer within a computer. It has memory, software, firmware, I/O, two crystals, and a CPU. Its function is to:
• Tell the computer to turn on, turn off, sleep, wake, idle, etc.
• Manage system resets from various commands.
• Maintain parameter RAM (PRAM).
• Manage the real-time clock.
Important:
Be very careful when handling the main logic board. Remove the battery when handling the logic board so the PMU is
not affected. The PMU is very sensitive and touching the circuitry on the logic board can cause the PMU to crash. If the PMU crashes, the battery life goes from about five years to about two days if the PMU is not reset. Refer to the next topic, “Resetting the PMU on the Logic Board” for the procedure. Many system problems can be resolved by resetting the PMU chip. The PMU reset button is located on the right side of the board, refer to the logic board diagram below.

Resetting the PMU on the Logic Board

Resetting the PMU (Power Management Unit) on the logic board can resolve many system problems. Whenever you have a unit that fails to power up, you should follow this procedure before replacing any modules.
1. Disconnect the power cord and check the battery in the battery holder (BT1). The battery should read 3.3 to 3.7 volts.
If the battery is bad, replace the battery, wait ten seconds, and then reset the PMU (refer to the next step). If the battery is good, go to the next step.
2. Press the PMU reset switch (S1) once on the logic board and then proceed to step 3. Do NOT press the PMU reset switch a second time because it could crash the PMU chip.
3. WAIT ten seconds before connecting the power cord and powering the computer on. If the computer powers on, go to the next step. If the computer does not power on, there is something else wrong with the computer, refer to the symptom/cure chart, “No Power” in this chapter.
4. Run MacTest Pro and return the computer to the customer.

Note: This entire procedure resets the computer’s PRAM. Be sure to reset the computer’s time, date and other system parameter settings before returning the computer to the customer.

fusionexr · Apr 1, 2006, 03:48 AM

Ok so I replaced the battery (which was completely dead), and reset the PMU switch and I still am getting the same results. I also tried a couple different sticks of ram with no luck either. Tried it with another OS9 hard drive, no dice here either.... I might just have to give up on it if it gets to be something more major... What else can I check?

Stogieman · Apr 1, 2006, 04:19 AM

It sounds like you have the "green light of death." Your power/analog/video board probably went out. Same thing happened to my iMac DV SE 400. Checkout this thread, it has a lot of good information.

green light of death revisited

fusionexr · Apr 2, 2006, 02:55 AM

Originally Posted by Stogieman

It sounds like you have the "green light of death." Your power/analog/video board probably went out. Same thing happened to my iMac DV SE 400. Checkout this thread, it has a lot of good information.

green light of death revisited

Thanks for the info... I think that's what happened too.... My buddy said he had a couple more laying around which is ironic so I will probably just go get another... Do any of y'all know a quick site to get the firmware updates for all the pieces to these computers? If/when I get another one I will update that stuff before running OS X again so I don't fry it again

Thanks much guys.