I have just fixed my screen flicker (Software only)

Question

First of all, please note the below procedure is to be tried at your own risk.
The basic idea is to add a custom refresh rate to the system (70Hz Vertical) and use it instead of the default one (60Hz).
What was my flicker like:
Continuous, felt like watching and old TV (European, 60Hz) and feeling the ripples. I had no sudden changes of backlight intensity, and the flicker became obvious when using a matte background image, usually grey or blue.
What I had done:
While searching for any clues on how to check/modify the display refresh rates, I found a thread (really sorry for not putting the link ... forgot it) where the poster recommended a small program (SwitchResX Control) to create a poll of faulty LCD manufacturers. I have downloaded the software and finally I managed to fix my flicker
Step 1:
Get the program at http://www.madrau.com/switchres/SwitchResXControl.zip. You should use the native resolution for the MacBook (1280x800).
Step 2:
In the program, go to the Custom tab. Press the + sign to create a custom setting. In the 'Timing Parameters' window, after making sure all the parameters are the same as the normal 1280x800 setting, set the vertical scan rate at 70. Also, check the 'Positive synch' check-box. Save everything and reboot.
Step 3:
Open System Preferences, then Displays. Now you should have the Refresh Rate drop-down option enabled (should be 60). Select the 70 setting. Save and reboot.
Step 4:
You should have a flicker-free display now.
Feel free to check http://www.iedutu.net/macbook for pics taken during setup and settings from my machine.
Please remember:
0. If anything goes wrong, select Factory Settings, save and reboot.
1. This thing worked fine for me. It might not work for you. If you have done all steps and still have a flicker, you might have a genuine hardware problem. Like I mentioned before, I did not have an extreme type of flicker, nor a random one.
2. This should be tried at your own risk. I think setting a different refresh rate cannot damage your hardware, but I'm not a hardware guy, therefore I hope nothing will go wrong with my MacBook too .
Have fun!
Cristian

Answer 1

I looked over a number of mac forums and I can say that there are two separate flicker problems:
1. Continuous flicker, obvious on a blue/gray wallpaper when dimming the brightness. Flicker not visible on full brightness, growing while dimming the display. At 50% brightness the display is very usable, flicker visible only if you are actually looking for it. My take this is a software problem (found few people saying the flicker is gone in Windows XP in bootcamp, but present in OSX).
2. Random flicker, ranging from almost visible to flashing screen. Comes at random times, with or without the power adapter plugged in. Can appear in all sorts of combinations/situations. I do not want to assume anything here, but I feel this is a hardware problem based on the YouTube clips I saw.
My case was the first one, thank God and hopefully it will stay like this, although I saw MacBooks on display with no flicker whatsoever.
On the second case, I think a trip to an Apple Service Center would fix it. Unfortunately there is no known faulty module that changed is fixing the problem for everyone with the random/continuous flicker. Everything from logic boards to invertors to displays were changed with mixed results. But it seems the invertor is being changed in most cases and most people are happy with the result.
My 2c.
Have a nice day!
Cristian.