2007 Imac LCD Screen Troubleshooting - Help!

[midorix]

I can use all of your help.

I have a 2007 24" 2.8ghz Imac with the LCD issue.

Yesterday morning, the bottom 3rd of the LCD went dark. I can still see the icons and such but the screen is very dark, almost like the PC's sleep mode.
The top of the LCD is fine.

After some searching, there's two possibilities causing this issue.

1) Bottom CCFL (backlight) went out
2) Power inverter problem

I'm leaning towards #1 since it's always the bottom 1/3 of the screen. If it's a power inverter issue, I assume it can cause issues in different areas of the screen. I'm still not 100% sure because when I put the Imac in the sleep mode and then take it out of the sleep mode, for brief one to two seconds, the bottom section is fine. If the CCFL is out, shouldn't it always be dark?

If you can help to confirm if its the CCFL (backlight), I assume I have to replace the whole LCD (I've seen some clever people replacing 20" IMac CCFL through soldering and careful handling of CCFL but I'm not sure if that's worth the exercise).
If I go replacing the whole LCD route, where's a good source to get them?
Is it possible to get new LCD parts or would I have to settle for refurbished or used?

Any help you can provide is greatly appreciated.

PS. I went through the typical troubleshooting mode (reset SMC/PRAM, check the brightness setting, etc. and nothing resolved it)

 

[ATC]

Can you post a picture? I only ask because when I first read your post I thought you described the same thing that happened to the 24" LCD in our early 09' iMac but after reading your post again I'm not so sure anymore.

Ours went dark in a non-uniform section roughly covering the bottom left quadrant (almost circular in shape) - see pic below (click to enlarge):



In my case, I think what happened was excessive heat over time from the CPU/GPU caused the LCD to do this. Nothing worked short of replacing the whole panel (a $600 job). Thankfully I took it in with less than a week left on my AppleCare.

 

[midorix]

This is what it looks like.

I used a white desktop background so that you can see where the darkness starts.
I think it may be a different issue but the solution may be the same.
I'll probably need to replace the whole LCD.

 

[ATC]

Yes, that looks like a different issue. That sucks, but hope you get it sorted out.

 

[ClemyNX]

I have the same model and my top third of the screen has been dim for 2 years now. But it's not THAT dark, I can still use it very well. Maybe the bottom lcd illuminate much more of the screen. I had looked at this issue and it's probably just the LCD, not the inverter. I'm going to change the screen at the end of the year when I'll give it to my parents after buying one of the new iMacs.

 

[midorix]

What's perplexing is the fact that for the brief second or two, it's fine when coming out of the sleep mode. I would really think that it should be dark all the time if the CCFL is out but then again, I have no idea how many CCFL are in this unit (just U-shaped tubes at the top and bottom or is there a another?)

But the above is what it looks like as well when I boot up with apple logo in the center.

Way too dark to be useable so I do need to get this fixed.

 

[ClemyNX]

Yes, just like mine it lights up for a second each time the screen wakes up. Maybe it's just a condenser in the LCD tube (there are just 2 straight tubes).

It's possible to change just the tubes but it's pretty difficult and potentially dangerous (mercury or whatever is inside is very toxic).

http://www.ifixit.com/Guide/Install...MC+2133+and+2210+LCD+Backlights+(CCFL)/5864/1

I'm going to follow this guide to replace the screen :
http://www.ifixit.com/Guide/Installing+iMac+Intel+20-Inch+EMC+2133+and+2210+Display+Panel/998/1

Hoping that it's not the inverter, in that case it'll be this :
http://www.ifixit.com/Guide/Installing+iMac+Intel+20-Inch+EMC+2133+and+2210+Inverter/999/1

 

[midorix]

Replaced it today with refurbished LCD purchased from Ebay and it solved the issue.

I hope this one lasts for at least next couple of years since this solution was still not that cheap.

I managed to clean out 5 years worth of dust and lint in the process.

If I feel brave, I may try to take a shot at fix the broken LCD by replacing the CCFL. We'll see.