Backlight failures on 20" Cinema Displays

Thanks for all the useful information.

One thing I found that I didn't see above: I had the short-short-long blinking with dimming at the top of the screen like many others. After reading many of the posts, I shut down and unplugged the monitor to no avail.

But when I tried to unplug the monitor without shutting down the computer it worked (at least for now). I doubt this is a recommended procedure, but it worked and it's cheap (Also I didn't let the computer rest as many have suggested - I unplugged it and plugged it right back in). The dimming and blinking ended.

Ok, I got the monitor back from the first time I sent it in. I called tech services again because there was no repair listed. I was told that the bulbs were replaced.

Not long after that, the problem returned. I called it in and this time was told that no repair was done the last time since the Apple Store where I took it did not give a description of the problem (I had called it in to Apple Tech and had it all taken down over the phone, had been told to take it in to the store and they only had to send it in.....hmmm).

This time I requested that a box be sent and I'd send it in from home. The young woman on the Tech Line was very helpful (I had been sent up a level since it was a second time on the same problem). I just got the monitor back and it works beautifully. I had to call in again to get them to interpret the letters and numbers of what was replaced. It was the inverter board. I was lucky in that I had bought the G5 tower and monitor at the same time and so the Applecare covers them both.

Overall I am very pleased with the service and cannot stress the need to buy the extended warranty on any major appliance. It has saved my monitor (not that long ago it saved my old G4 400Mhz TiBook that I gave my nephew for college. He is still using it and it is still pristine. He says the most asked question is why are his hinges different than theirs....I told him to tell them that it was a build to order laptop.

Recently had the short-short-long backlight failure on my 20" (plastic) ACD.
Unplugging it and straightening the cord connection seems to have fixed the problem.
A cord support (keeping the cord/connector at 90 degrees to the video port) would seem to be a good idea.

1ghz G4 MDD (FW800); 1.25GB; 80GB and 120GB HDD; GeForce4MX; 20" Cinema Display (ADC) Mac OS X (10.4.7)

Thanks! I had the exact same situation (except I had gotten the new inverter from Moniserv). Tried your work-around and that did the trick for me too. However, as with you, it's only good until you put the computer to sleep. Then you have to do it all over again.

But I think this might show the problem is not bulb related. Wouldn't a bulb be either good or bad? Or do these bulbs go progressively dimmer? If it was a burned-out bulb, the work-around wouldn't work. So we've replaced the backlight inverter, and the bulbs are probably okay. What's next?

I had the short-short-long blinking with dimming at the top of the screen like many others. I replaced the inverter with one from LCDparts.com (thanks guys for selling these) and the blinking has stopped. However the top of the screen still seems a little duller than the bottom, although I don't think it's as bad as before the repair. Does anyone know a utility I can run that will check that all the bulbs are still working in there?

After over 12 years of bullet-proof desktop Macs, my luck seems to be running out recently. First my G4MDD logic board died, then my G3 iBook succumbed to the well-known LCD screen failure, then my G4 12 inch PowerBook did it's famous 80GB hard disk 'light-saber noise' failure, now this. I'm starting to think twice about splashing out on a new MacBook Pro in the next month or two...at least the G4DA and beige G3 are still going strong.

Thanks.

This may be a short term fix that will cost you big $$ soon.

I had the same problem and did the same thing that you did a few times then my video card croaked. This was the nVidia geForce Ti 4600 with 128MB of ram that came stock with my machine. It cost me $250 to get another card and the screen still blinks. ( I think that I'll just let it keep blinking!)

Graham

How did u get on with the backlight problem on your 22" display I have the same problem with mine 2.5 years old - model number A1038

Hi Andrew,

I only switched out the inverter, I have not changed the bulbs yet... I have to agree with 'kerplunk1' that this trick wouldn't work if the bulbs were completely burnt out, but I'm probably going to give it a shot anyway.

So, I haven't had the blinking return, but I still have to change the display prefs if I want the screen to look normal.

I don't know what I'm going to do about it, actually! I'm still on a G4 and it's running a bit slow for my workload these days, so I might be getting another computer and monitor soon anyway... But I'm not giving up hope yet that something will eventually work for this 20 in., I'm not about to trash it! 🙂

Hi kerplunk1,

I'm so glad this has worked for other people with the same problem!

I agree, I don't know how it could be the bulbs... this trick works consistently. I was just going to change them anyway as a last-ditch effort! I've been looking for more information on the bulbs, maybe they have several settings like a 3-way lamp lightbulb and are not functioning properly? I haven't found any information about them yet, but I'm still looking...

The flashing powerlight has stopped, my screen was dimming anyway so I guess I spent the money on the inverter to stop my flashing light... Whoo hoo!

Duel 867 MHz PowerPC G4 Mac OS X (10.4.6)

This definitely worked for me - straightening the cord. Starting and restarting, using PRAM, waiting etc didn't seem to do anything. But examining the connections between the display and my G4 - the display end is solidly in, but removing the G4 end I noticed it was bent down. I moved it back straight (clicking the back into the plastic notch between the connector and the cord), put a folded business card underneath to keep it straight and it's fixed.

I'm here just to report again one just over two year old 20" Apple Cinema Display with failed backlight. None of the tricks described here worked for me. The upper half of the screen remains dim and the power button keeps flashing short-short-long... I'm very dissapointed with Apple, I would have expected a monitor that costs over 1500 euros to have a little.. no a lot longer lifespan.

Hi all!

I have a 17" flat panel that came w/ my G4... it was blinking 2 short 1 long with the lower half of the monitor darker than the top...symptoms that have been described in this thread.

I wanted to reinforce a solution that I tried after reading about it here....

I went to http://www.lcdpart.com/doc/inverter.html and purchased the correct replacement backlight inverter.

They had a PDF document that outlined how to change it.

It was pretty simple. And most importantly... it worked!

I am gratefull to those who postted the solution... this cost around $120 but it saved the purchase of a new monitor.... I am very happy!

Just to add my two penny worth - I too had the dimmed monitor/flashing light problem (with a 17" display) and after a bit of reading was prepared to go down the self-repair/new inverter route when I happened upon a suggestion to open the monitor preferences and play with the brightness a few times - and bugger me if it didn't sort the problem out - weird.

I did all of this in OS9 and then rebooted in 10 and now everything is back to normal. Give it a crack before you stump up for a repair.

An update on progress with this problem. I was able to fix this for up to 1 week at a time using the various strategies discussed by everyone above, including straightening the cord, restarting cold, the most successful being restarting after taking out all the cords (power cord for computer, cord to display) - but eventually the problem became resistant to all attempts to right it.

I rang my local Apple store, asked them if they had a replacement inverter board, they had the part, and they put it in - my screen is cured. It cost me less than it would have cost had I bought the part from Moniserv from the USA. I paid $90 Australian dollars for the part (about $65 US I think) and could have put it in myself but decided to pay Apple a little extra for the labour (so that they would be responsible if it didn't work). So my experience is that it is worth asking you Apple store before you start buying the part - they seem to have it now.

Hope that helps someone.

Power Mac G4 & Powerbook G4 Mac OS X (10.4.7)

I had the familiar dimmed top section of my 20" Cinema Display. The problem went away for a short time after plugging and unplugging the monitor. After the problem reappeared I could not correct the dimming. I ordered the replacement Backlight Inverter from lcdparts.com. Opening the monitor case and replacing the board was generally very simple. Not a big deal. You will need the proper size allen wrench.
After replacing the board I booted up and had no blinking light anymore. Good. However the screen remained dim at the top. ****. No good. Considered paying for an RMA from lcdparts and shipping it back. Still did not know if it was the backlights or the inverter though.
Say the Work-around post and thought it was worth a try. Changed the brightness to its lowest. Changed the res to some of the other settings. Heard a buzzing.... changed back to highest res and upped the brightness. Low and behold - NO dimming.... Not sure if the problem is gone permanently.... I will post back....