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I have just fixed my screen flicker (Software only)

13256 Views 14 Replies Latest reply: Oct 28, 2007 2:44 AM by Guy Reid RSS
iedutu Level 1 Level 1 (35 points)
Currently Being Moderated
Jul 26, 2007 12:48 PM
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 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 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!
Black MacBook 2.16Ghz, 2Gb RAM, Mac OS X (10.4.10), 1 dead Adapter until now ...
  • walter59 Calculating status...
    Currently Being Moderated
    Jul 27, 2007 8:27 AM (in response to iedutu)
    dear cristian,

    i have just followed your instructions concerning the flickering of my screen. Obviously it works! Thank you


    Macbook, Mac OS X (10.4.10), privé
  • Alex Zakrevsky Calculating status...
    Currently Being Moderated
    Jul 28, 2007 12:10 PM (in response to iedutu)
    It worked for me as well!
    I have a brand new MacBook, that had a screen flickering. I've done what you suggested. Changed refresh rate over to 70. Reboot. And here it is, no screen flicker whatsoever.

    Thank you!
    Mac mini G4 1,25; MacBook Core 2 Duo 2.0, Mac OS X (10.4.10)
  • Technarch Calculating status...
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    Jul 28, 2007 11:37 PM (in response to iedutu)
    iedetu, why do you recommend 'positive sync'? the 60 hz rate uses negative/negative. I tried 70 hz with negative/negative and it works fine but not for the flicker problem I have.. I have an original core duo yonah macbook, so I am not affected by the core2duo flicker. Just wondered why you specified positive sync.

    Doesn't fix backlight issues unfortunately.
    MacBook 2.0 White, Mac OS X (10.4.10)
  • Dubdog Level 1 Level 1 (35 points)
    Currently Being Moderated
    Jul 29, 2007 7:47 AM (in response to iedutu)
    Thanks for the tip. I've already had the inverter changed for screen flicker several months ago so was disappointed when it seemed to reappear (although not as bad as previously and it wasn't continuous). This looks like it's done the trick but, as I say it wasn't continuous, so I'll have to give it a bit of time and if I get a hint it hasn't worked I'll post back here to let you know.

    Thanks again.

    Message was edited by: Dubdog
    G5 PowerMac & MacBook
  • Paul J. Hart Calculating status...
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    Jul 29, 2007 3:26 PM (in response to iedutu)
    Well, i tried this fix earlier today and all day, no flicker

    However, as i type this message the flicker is coming back so I am afraid its not a permanent solution at least not for me!
    Macbook Core Duo 2, Mac OS X (10.4.10)
  • Dubdog Level 1 Level 1 (35 points)
    Same here, my flicker back so this isn't a permanent fix (and as the flicker is intermittent it's difficult to say whether it was fixed in the first place).

    Just contacted Apple UK who first tried to suggest the flicker was normal to which I replied that my machine has been fine since the inverter was replaced a while back but now the flicker has returned (all be it not as bad as previously). After running some trouble shooting that didn't sort the problem it's now going to be booked into an Apple Service centre.
    G5 PowerMac & MacBook
  • Dubdog Level 1 Level 1 (35 points)
    Currently Being Moderated
    Jul 31, 2007 2:37 PM (in response to iedutu)
    Thanks for you input Cristian. Didn't mean to sound ungrateful in previous comment. I'd give you a 'helpful' if it had been my post originally.

    Hope your MacBook stays trouble free.
    G5 PowerMac & MacBook
  • Ste Thornley Calculating status...
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    Aug 5, 2007 3:58 AM (in response to iedutu)
    Cheers Mate, this worked a treat, cant even see the wave now on the Grey Apple start up screen. Also I cant see any side effects, at 1st I thought the screen looked a bit blurred but I think that was down to my Tired eyes, typing this msg now and the screen looks amazing, one of the best screens i have ever seen.

    many Thanks for the excellent advice

    Macbook core2duo white, 20" Imac, Choose
  • Guy Reid Calculating status...
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    Oct 28, 2007 2:44 AM (in response to iedutu)
    SwitchResXControl worked for me in Tiger. Doesn't seem to in Leopard. In fact it even crashed on startup once.
    G4 Dual 867 MDD 2G RAM, Mac OS X (10.5)


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