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Connor
Aug 22, 2008, 01:10 PM
Hi
I have a macbook that was given the ol beer in the keyboard treatment and went dark with a ghost image, before I bought it, leading me to believe that it was the inverter board had blown, I bought one online and replaced it but to no avail. The previous owner obviously had very little knowledge as they left a few screws out on reassembly but I don't think they should matter a lot. I could of course use it with an external monitor but kind of defeats the purpose of a laptop. So would like to get the display working without having to buy a new display. I cannot seem to find out if it is possible to replace the backlight, if this is the problem, or to find one for sale online, even on the excellent ifixit site. It is a 2Ghz intel core 2 duo.
If anyone has any ideas I would be very grateful,
Thanking you,
Connor



Jabberwocky246
Aug 22, 2008, 04:13 PM
There are four possible causes for the screen to be dark (at least that I know of).

1) Most common is the inverter, which you have already replaced.

2) A number of posts report the dark screen issue is fixed by turning up the brightness control which had accidentally gotten turned all the way down.

3) For non-LED backlight screens, there will be one or two (although I've seen as many as four) cold cathode fluorescent tubes that can go out. The ends turn black just like a dead fluorescent bulb from a ceiling light fixture. While it is entirely possible to replace the CCFL bulbs in a screen, I can't recommend it. I've done it a couple of times and it was a nightmare. Imagine handling a 12 or 13" long piece of pencil lead.

4) Lastly, the circuitry on the motherboard can go bad, especially from a liquid spill. I am using a Macbook Pro that had a bad backlight that wasn't fixed by a new inverter. I swapped screens with the same results, leading me to conclude it was the logic board. With nothing to lose, I tried resoldering the connection where the monitor plugged in to the logic board and was able to revive the screen. Usually though, you will be looking at the cost of replacing the entire logic board if this is the case.

Since you already know the inverter works, my recommendation is to pick up a replacement screen (you can find them on eBay for under $200). Obviously, that's a lot of money to blow if it ends up not being the problem, but it's cheaper than a logic board and far easier than trying to replace the individual CCFL bulbs.

Borrowing a screen from a friend for testing is an alternative, but it would have to be a REALLY good friend to let you dismantle his computer.

Full replacement instructions are available at www.ifixit.com.

Good luck.

Connor
Aug 22, 2008, 04:34 PM
Hi Jabberwocky,
thanks for all the suggestions. I have already tried turning the brightness control. How can I tell if it is a non LED or not? I would be willing to replace the bulbs, I believe I have the wherewithal to do it. Do you know how I might get the replacement bulbs? I will have another look at the motherboard to spot other damage.
Connor

Jabberwocky246
Aug 23, 2008, 02:22 AM
Hi Conner,

To see if you have an LED monitor, try doing a Google search on your model number located on the bottom of your laptop (see http://www.ifixit.com/info/ID-your-Mac/370). You may be able to find the specs on Apple's web site or on www.ifixit.com.

If you determine you have a display with cold cathode backlighting and are very brave (or have a case of giganticus testicularus), you have a couple of options for replacement tubes. Take a look at this site for a description of the replacement process as well as a link to a CCFL vendor - http://www.insidemylaptop.com/replace-ccfl-backlight-bulb-in-laptop-screen/. You can find a number of vendors for CCFL bulbs by doing a Google search but you will want to disassemble your screen to determine the exact size and number of tubes.

Alternately, you can try buying a cold cathode light for the inside of computer cases like this one: http://www.xoxide.com/dual-white-cold-cathode-kit.html. While the length may not be correct, it will probably work and best of all, it's only $6.99!

Again, best of luck to you.