[diehlr]

I've got an old Bondi rev. A iMac that is suffering from the "green light of death" syndrome. In other words, when shutting down or restarting the computer, the monitor light stays green instead of switching to orange/amber and flicking back over to green again. The consequence being the monitor doesn't turn back on. After unplugging the power cord and plugging it back in, it comes up fine 100% of the time.

I've been doing research on this issue and most people point to a faulty analog video board on the monitor. Specifically, the flyback transformer on the back of the CRT neck. I don't believe this is a valid explanation for these symptoms, since the machine will come on just fine when power cycled.

I ran across a more reasonable explanation on a couple of sites that pointed to faulty relays on the analog video board, which makes much more sense. My guess is the relays are sticking for some reason until the machine is powered all the way off, causing them to reset.

Does anyone know from experience if in fact the relays are to blame? I would very much like to repair this thing myself if I can locate the faulty parts and order suitable replacements. I'm experienced in soldering and doing work on circuitry, so this isn't a problem. But I don't really want to take this thing all the way apart without being reasonably sure I am looking in the right place.

Any and all technical information (the more technical and detailed the better) is appreciated.

[Nivag]

i'm not going to be much help to you here, except to say i've read the same thing and could work out which was the best route to take, so i took the extreme way of sorting this by ripping the guts out of the iMac and placing them in a different case and using a external monitor.
not much help to you, but to say you're on the right track.

[Detrius]

Have you tried resetting the CUDA chip on the logic board? It's worth a shot.

A few things to note here: the CRT can kill you. If you do not know how to properly discharge a CRT, you should not be doing any work inside the display. Also, if you break the neck, the entire tube will forcibly implode.

If you have another Bondi iMac around, try switching cans in the machine just to verify where the cause of the problem is located.

More than likely, the cause of your problem is the Analog/Video board. Looking at the machine from the rear, the A/V board is the one on the right. The power supply board is on the left. The flyback transformer is the black thing at the top of the board with the red cable running to a suction cup that connects to the CRT.

You will have difficulty finding much information on which component on the board is likely the cause of your problem as we technicians would not fix the board; we would replace it.

I would *highly* recommend letting someone with experience fix your machine for you. However, if you are going to fix it yourself, Preowned Electronics is a great place to get Apple parts (cheaper than Apple and 6 month warranty, but you will have to call them).

If I remember correctly, the Rev. A board has the wire connections running along the side of the board next to the CRT and the Rev. B has the wire connections running along the bottom of the board. If you order the part, you will have to know this.


In closing, I am going to reiterate that these things can kill you. You really should let someone with CRT experience replace the board for you.

[diehlr]

Thanks for the word of warning, however I've already done a lot of work around the monitor and discharged the CRT. Actually, I left it unplugged for 3-4 hours and the CRT discharged itself completely. So, no danger there. Replaced the power supply on suspicion that the relays on it were bad, but that wasn't it. So, ordered a replacement flyback transformer. $39.99 from http://www.fbtmaster.com. Should be here tomorrow. Will solder it in and see how it goes. No big deal, I have experience soldering. I'll let everyone know if this fixes the problem once and for all.

[ValVashon]

It sounds to me like that might be your problem. Last time I worked on TV's/Monitors, CRT's did not discharge themselves after a few hours. So a faulty flyback might allow the CRT to discharge itself through the flyback. Good luck with it. I have a Bondi with no problems yet (fingers crossed) but I'm watching threads like this for what to do about future problems.

Val

[THE MAC GOD]

I've got a Bondi and never had that problem... although I've heard that it is the video... not sure...

[diehlr]

Replacing the flyback transformer cured the problem.

Got the flyback from http://www.fbtmaster.com, cost was $40 shipped. Not too bad, cheaper than a new analog board! Took an hour or two to get the old one off and solder in the new one. Nearly all of that time was desoldering the old one, I'm not too good at it. Only took about 5 minutes to solder the new one in place! Entire process was not hard at all, just time consuming.

Part number is 6174Z-1003G.

[UrQuattro]

it should be the analog board. when i was working as a mac tech for a shop that did a lot of 'out of warranty work', we would see this problem ALL THE TIME...

the boards themselves should be fairly inexpensive, and if you know how to take an imac completely apart, it really isnt all that difficult. just be REALLY careful around the CRT tube...

whenever we would have a no video issue like that, whether it was exactly what was described, or just no video, or a light that would stay orange, etc etc, we would just swap out the entire analog board, which includes the piece on the end of the crt neck...

[diehlr]

Yep, I outlined the solution above. It was the analog board, specifically the flyback transformer. Replaced it (the flyback) and it works fine now.

Just to note, replacing the flyback seems to be the cure for two sets of symptoms on the Bondi iMac. I was sure it fixed #1 by reading on the Internet, but wasn't sure about #2 until now.

1) The monitor goes black part-way through bootup, and the green light comes on. ie- the monitor never functions.

2) The monitor works fine until restarting or shutting down, after which it stays black and the green light comes on. Unplugging the computer and plugging it back in causes it to work again.

[Detrius]

Originally posted by diehlr:
Thanks for the word of warning, however I've already done a lot of work around the monitor and discharged the CRT. Actually, I left it unplugged for 3-4 hours and the CRT discharged itself completely. So, no danger there.

Originally posted by ValVashon:
It sounds to me like that might be your problem. Last time I worked on TV's/Monitors, CRT's did not discharge themselves after a few hours. So a faulty flyback might allow the CRT to discharge itself through the flyback.

Yes, newer macs are *supposed* to discharge themselves automatically. (This is newer in comparison to the Mac Classic, etc...) However, this is done through the flyback transformer. In most cases where the Analog/Video board needs to be replaced, the flyback transformer is the cause of the problem, and therefore you should not rely on this feature of these machines. In addition, once you have the anode cap disconnected, the CRT will build up another small charge. Technically, the danger has been reduced due to the auto-discharging CRTs. However, this could also be like assuming a gun is not loaded and pointing it at someone and pulling the trigger. What if you were wrong? You have a problem.

If you don't know how to safely discharge a CRT, DO NOT ATTEMPT THIS REPAIR YOURSELF.

[ecrelin]

I have two slot loaders that display the pulsing power light syndrome. They will never come on though, unplugging, cuda reset, battery removal, etc. and worse yet I got a whole replacement analog board and it did'nt fix it. The board I got was a refurb so the flyback may not have been replaced, I have been on these boards for years seeing these symptoms and no one has gotten this far in solving it. Kep up the good work and I'm prayin' that this may be the answer, I'd hate to chuck these two machines for nothing.

[quizzyjones]

CRT's can hold a charge litterally for years. Also, if the flyback is to blame you are better off replacing the entire board. Typically these boards from Apple are about 115 dollars and can be had from preowned for about 80. Just make sure when you order your board you get the right Rev. of the board. Also when discharging the CRT always ground to the chassis of the machine, never earth grouding. Also do not have a static bracelet on or be grounded in anyway. But to be perfectly safe, take it to an apple dealer ar a service provider and let them take care of it for you.

[sadas]

I've got a dead iMac with similar symptoms, but the hard drive fails to spin up. Dead screen, no hard drive spinning, nothing except the green light.

Does a failed analog video board also affect power to the HD?

j mcd

[Detrius]

Originally posted by ecrelin:
I have two slot loaders that display the pulsing power light syndrome. They will never come on though, unplugging, cuda reset, battery removal, etc. and worse yet I got a whole replacement analog board and it did'nt fix it. The board I got was a refurb so the flyback may not have been replaced, I have been on these boards for years seeing these symptoms and no one has gotten this far in solving it. Kep up the good work and I'm prayin' that this may be the answer, I'd hate to chuck these two machines for nothing.

The slot-load iMacs are completely different from the tray-load iMacs, even though they look pretty similar on the outside. On the slot-loaders, it's no longer just an Analog/Video board; it's a Power/Analog/Video board. The power supply is on the board now. In addition, there is also a down converter board. Also, bent pins on the CRT can cause strange behavior. In addition, the PAV board on the slot loaders needs to be calibrated to your machine, and this requires non-publicly-available software.

On the slot load iMacs, the following four parts (in order of likelihood) can cause the above mentioned issue:

1-The power/analog/video board
2-The logic board
3-The down converter board
4-The CRT

The down converter board is the board that that is virtually attached to the logic board. The best way to know what is causing your problem requires having one good machine and an identical dead machine. Switch the logic board and the down converter board. If the problem sticks with the machine, replace the PAV board. If the problem follows the IC boards, separate the down converter board and the logic board. It is most likely at this point that the logic board is the cause of the problem.

It's virtually impossible to tell which part is bad based on just the symptoms. There are technically even voltages that you can check, but that's not even reliable.

Oh, and installing 10.2 or later on a slot-load iMac without the firmware update can cause this too (in extreme cases).

[bmuki]

Our grape 400 MHz iMac DV is also dead with the same description as sadas above. Before dying, I noticed for a week when I came into the office, overnight OS X was somehow restarted to the login screen. After a few days, it restarted in front of my eyes. I witnessed this restarting about 3 more times over about 2 days. The final time, it simply would not turn on except as described by sadas. Now pushing the power button only amounts to flashing the green light of death maybe 3 or 4 times.

The Apple Store quotes an estimate of $200 if it's just the power supply and $300 if it's the logic board... the fair eBay price seems to be about $400. I weighing this vs. the $700 eMac (government price). (Well, I'd wait for an eMac update, which may happen soon.)

Has anyone recovered from this green light problem?

[Detrius]

Originally posted by sadas:
I've got a dead iMac with similar symptoms, but the hard drive fails to spin up. Dead screen, no hard drive spinning, nothing except the green light.

Does a failed analog video board also affect power to the HD?

j mcd

Try resetting the PMU. The HD power comes from the down converter board which gets its power from the logic board. But the logic board gets its power from the PAV board.

These can be difficult to diagnose without a spare... at our tech shop, we have a good iMac that we keep around just for this. It saves a significant amount of time to just be able to switch parts on these things and find out.

[Detrius]

Originally posted by quizzyjones:
Just make sure when you order your board you get the right Rev. of the board. ... But to be perfectly safe, take it to an apple dealer ar a service provider and let them take care of it for you.

There is an LG CRT and an HH CRT. Some of the boards have switches on them. The LG CRTs say LG on the CRT and on the Down Converter Board. The HH PAV board has a four leaf clover on it.

I would recommend taking it to someone who is Apple Certified or has been in the past. If they don't know the difference between a flyback transformer, an anode cap, and the neck, then they shouldn't be inside the thing either.

The CRT is something you need to have a healthy fear of. Don't try to fix a power supply yourself. Don't try to fix a display yourself. If you read that and thought "how hard could it possibly be," then it applies to you. It's not difficult; it's dangerous. (I can replace a PAV board on a slot-loader in 45 minutes. Fixing a bad trackpad on a TiBook is difficult--3 hours.)

[Detrius]

Originally posted by bmuki:
Our grape 400 MHz iMac DV is also dead with the same description as sadas above. Before dying, I noticed for a week when I came into the office, overnight OS X was somehow restarted to the login screen. After a few days, it restarted in front of my eyes. I witnessed this restarting about 3 more times over about 2 days. The final time, it simply would not turn on except as described by sadas. Now pushing the power button only amounts to flashing the green light of death maybe 3 or 4 times.

The Apple Store quotes an estimate of $200 if it's just the power supply and $300 if it's the logic board... the fair eBay price seems to be about $400. I weighing this vs. the $700 eMac (government price). (Well, I'd wait for an eMac update, which may happen soon.)

Has anyone recovered from this green light problem?

Your issue sounds a LOT like a PMU/logic board issue. There is a button on the logic board that you can get to by opening the flap on the bottom. You also should check to make sure the battery isn't dead.

To reset the PMU, unplug the machine from power. Push the button on the logic board. Wait 15 seconds. Plug it back in and push the power button.

[bmuki]

Hi Detrius,

I tried pushing the PMU reset button as you described. Nothing. We went out to Radio Shack and got a new battery (identical brand as the old one). Still nothing.

We will just have to take it in to the Apple Store.

Thanks for the advice. It was much appreciated.

[allotrope]

Don't want to highjack the thread but I feel that you guys might be able to help. I have an iMac (slotless graphite) with the internal video is dead. If I connect an external monitor via the video out, I can view the desktop (built-in video is still dead). The Apple Service rep said at first that it was the video board that was dead. After waiting over 3 weeks for the part I get a call to say that it is not the video board but the main board that is dead???? There is nothing else wrong with the system other then the dead internal video. Note that I was in the process of installing OSX on brand new HD (old one blew up with known problem with chip blowing up ) I just want to know if this really sounds like a bad motherboard? They want $400 CDN for parts and labour.


Thanks.

[Detrius]

Originally posted by allotrope:
Don't want to highjack the thread but I feel that you guys might be able to help. I have an iMac (slotless graphite) with the internal video is dead. If I connect an external monitor via the video out, I can view the desktop (built-in video is still dead). The Apple Service rep said at first that it was the video board that was dead. After waiting over 3 weeks for the part I get a call to say that it is not the video board but the main board that is dead???? There is nothing else wrong with the system other then the dead internal video. Note that I was in the process of installing OSX on brand new HD (old one blew up with known problem with chip blowing up ) I just want to know if this really sounds like a bad motherboard? They want $400 CDN for parts and labour.


Thanks.

Open up the Apple System Profiler and see if the ROM version is 4.19f. I suspect that it is not. You will need a copy of OS 9.1 or later on your hard drive to install the firmware update:

http://docs.info.apple.com/article.html?artnum=75130

A note to everyone else running slot-loaders: if you don't have this firmware update, the same thing could happen to you at some random point in the future. Specifically, the video goes weird when you install 10.2 or later. Sometimes the internal video is dark; sometimes it's gone but external is fine; sometimes external is bad too. Those are the tough ones, but it is still possible to get the firmware update installed (it requires another board that does not have the firmware update).

[ralphh]

Originally posted by Detrius:
If you don't know how to safely discharge a CRT, DO NOT ATTEMPT THIS REPAIR YOURSELF.

I just want to ditto this. A CRT CAN KILL YOU IF YOU DON'T PERFORM THE PROPER DISCHARGE PROCEDURE.

Leaving the system turned off is NOT sufficient to guarantee discharge the CRT. There is a discharge resister built into the board to try to protect you, but it can fail like any other component and you can't tell it's failed until you touch the anode cap.

One of the guys I worked with doing Mac repairs got laid out in the floor because an iMac with a defective discharge resistor got him.

A CRT that lacks or has a defective discharge resistor can retain the charge a very long time. An uncle of mine who did TV repairs many years ago got knocked unconscious reaching inside a TV set that had been stored in an attic for 6 MONTHS.

When working with high-voltage electronics (15-40 KV) the rules are different than when working with low-voltage electronics.

-Apple Certified Repair Technician

[GeeYouEye]

Originally posted by ralphh:

When working with high-voltage electronics (15-40 KV) the rules are different than when working with low-voltage electronics.
[/B]

Except it's the current that kills you, not the voltage. You can make a capacitor out to aluminum foil and styrofoam cups. Hook it up to a Van de Graff generator, and it will discharge 20 KV. But there's no current so it's only a minor shock.

[Detrius]

Originally posted by GeeYouEye:
Except it's the current that kills you, not the voltage. You can make a capacitor out to aluminum foil and styrofoam cups. Hook it up to a Van de Graff generator, and it will discharge 20 KV. But there's no current so it's only a minor shock.

Yes. But the CRT is a freaking huge capacitor that can hold large amounts of electricity. My coworker has a scar on his arm from when he carelessly reached across a 9" Mac Classic that hadn't been discharged.

We can't stress enough that casual amateur techs should not be messing with the inside of a CRT. It's the high voltage that makes it jump out and get you when you aren't expecting it. It's the large amount of stored electricity that puts you on the floor.

[Paul McCann]

Just a quick clarification of the points above (re installing 10.2+ on a slot-loading iMac without first updating the firmware): it's not only *installing* 10.2+ on such a machine that can cause the video to die. I've managed to temporarily kill a couple of slot-loaders by simply *booting* from a firewire disk that has 10.2+ installed -- both times I had the bright idea that I could just boot from 10.2+ and then use CCC to splatter the internal drive. Sheesh: you'd think I'd learn after the first one...

Recovery from the problem isn't too awful: as per the above posts, just connect an external monitor, update the OS to 9.1 if required, then the firmware to 4.1.9 (search on apple's software page for "imac firmware updater"), and then you'll be right to boot+splat from the firewire drive. And the video will magically come back to life.

Aaah, memories...

Paul

[Detrius]

Originally posted by Paul McCann:
Recovery from the problem isn't too awful: as per the above posts, just connect an external monitor, update the OS to 9.1 if required, then the firmware to 4.1.9 (search on apple's software page for "imac firmware updater"), and then you'll be right to boot+splat from the firewire drive. And the video will magically come back to life.

Sometimes it is aweful, as sometimes the external video doesn't work either. However, the video does magically come back to life once the update is installed.

[B3dd]

iMac 333 after upgrading to max ram orange light of dead

When i was upgrading this machine to panter it needed more ram so i took it apart and put the two kingston 128 modules sodimm in. I followed up the procedures, antistatic etc. When i put it togtether it coudnt start up, no hd spin, fan was running, powerup with usb keyboard worked, and green licht on logicboard, check for power on hd cable connector was 5v. put in the old ram same effect, with no ram... Yes cd spin !! and one beeep. the battery is 3,5 v, reset cuda no effect, I think i narrowed it down to the processor board. Could i killed all mij 4 ram modules or is it in the processorboard or logic board?
any suggestions??

[graphiteman]

I had some fun with my recently acquired iMac 350 this afternoon. I booted into the Panther install disc, and it told me I needed a firmware update. No problem, I said. I quit the installer, and the computer promptly hung. After rebooting, there was no video. However, after some playing around, I discovered that the computer would actually boot up, just without video. How did I get video back? I discovered that putting the computer to sleep and waking it up brought it back - to a degree. The video was either blurred or extremely dark, though usable enough to run updaters as needed. I went ahead and updated to 9.1 and installed the firmware update, but it was still very dark when booting into OS 9. On a whim, I went ahead and booted off of the Panther CD again and things seemed to be normal. I then installed, and it seems to be working fine. I love happy endings. :-)

Am I correct in assuming that, once the firmware has been updated and the issue fixed, the problem should never return? (fingers crossed)

[mrehab]

My experience is contrary to how Macnn.com characterized the Green Light of Death (GLD) as to a minority of iMac owners. I bought 3 iMacs (Bondi, 266 and 400 mhz) and all suffered that fate. It cost $300 to fix the Bondi and $300 to fix the 400 mhz. I trashed the 266. I suspect Apple knew about the problem all along and an enterprising lawyer could get some refunds.

[Detrius]

Originally posted by graphiteman:
Am I correct in assuming that, once the firmware has been updated and the issue fixed, the problem should never return? (fingers crossed)

Yes. It should not return.

BTW, it says in the Readme file that you needed to do the firmware update.

[Detrius]

Originally posted by mrehab:
My experience is contrary to how Macnn.com characterized the Green Light of Death (GLD) as to a minority of iMac owners. I bought 3 iMacs (Bondi, 266 and 400 mhz) and all suffered that fate. It cost $300 to fix the Bondi and $300 to fix the 400 mhz. I trashed the 266. I suspect Apple knew about the problem all along and an enterprising lawyer could get some refunds.

The thing is that the "green light of death" is the response to just about any part in the machine going out: the CRT, the PAV board, the down converter board, the logic board. All that is left in the machine is the hard drive, RAM, and CD-ROM drive. Also, sometimes, a PMU reset fixes the problem. So, there will be no legal action due to the "green light of death" as there is no one part that is consistently going out.

BTW, every mac that has ever had an Analog/Video board in it has had problems with the Analog/Video board going out. Monitors go bad. If you don't want to deal with this, buy a Power Mac so you can just replace the monitor when/if it dies on you.

There will also be no legal issue for hard drives that die after 5 years or cars that only last to 300,000 miles.

[Link]

Thing is, unlike regular CRT monitors, it dies out in about 1/3 of the time.

It seems to be common knowledge that apple's displays are plagued with the problem though. It happened with both the jellybean style AND ADC crts >_<

[applekid]

The MacNN Forum seems to have the best discussion about GLOD going on, so I decided to ask my question here.

I recently upgraded my Bond Blue iMac with a 40 GB HD and 512 MB of RAM. I then installed Panther on an 8 GB partition with the latest firmware installed previously. All went well for about a week or two. Then I rebooted one day and GLOD reappeared!

I let my iMac discharge for about two weeks since that "cured" the problem many times before. Today, I re-booted and it still has GLOD. But I've noticed something after installing Panther on that iMac. After the Apple icon screen shows up and disappears, the monitor flickers (I think it's changing resolutions). Before it moved on problem free, but this time the iMac's CRT turns off because of GLOD. I was wondering, if it is possible to somehow not make the iMac flicker during the boot sequence?

And, do I need to keep the iMac plugged-in to discharge?

Thanks.

[georgeryp]

I have a 350MHz blue slot-loading iMac and since I don't have another one to swap parts with I'm thinking about taking my chances and buying, say a $40 PAV board on eBay, to see if I get lucky and it fixes it - but to increase my chances do you have the info about checking the voltages handy or do you have a best guess on what to replace given these symptoms:

It used to switch off intermittantly but now it is totally dead except when you first plug it in - a green LED on the logic board near the RAM (marked "+3.3V - DS11") blinks really quick but then nothing - no power button light ever, dead.
I tried "Zapping PRAM", CUDA reset w/power button but that did nothing.
The battery is good... any ideas?

[Lancer409]

good luck

[macaddict0001]

I just read this thread and I have to say why the heck was this guy sticking a sodering iron into the switch of a 60 000 volt 9 amp capacitor conected to his head.

err hyperbole aside this guy is lucky to be alive.

[DAlex]

diehlr,

I've done the same as you and replaced the flyback - worked perfectly. I was lucky and found an excellent step-by-step guide (I cannot remember the website) to doing the work and also made a discharge tool as directed in the apple repair manuals.

As others have said it can be dangerous and is not a casual repair in so much as the discharging is concerned. The rest of the job is fun - dismantling the imac, desoldering/soldering, rebuilding - especially when it works

DAlex

[DAlex]

Originally posted by macaddict0001:
I just read this thread and I have to say why the heck was this guy sticking a sodering iron into the switch of a 60 000 volt 9 amp capacitor conected to his head.

err hyperbole aside this guy is lucky to be alive.

I got the impression that he had discharged the imac, dismantled it, removed the video board and then did the soldering job - if not then you are right, very lucky