Apple Service replaces 24" LED LCD with 24" iMac screen?

Discussion in 'Mac Accessories' started by kretek, Sep 4, 2009.

  1. kretek macrumors member

    Oct 15, 2008

    I had my 24" LED screen replaced at my local Apple Service Provider due to a speck of dust.

    The technician was insistent that the screen need only be replaced and not the whole unit.

    Well I received the unit back today, and I'm sure my eyes were not deceiving me as the screen did not appear to be a LED screen. The screen does not appear as bright as before and the text not as sharp.

    Secondly, the heading in Display preferences says iMac, and the native display profile also says "iMac", no LED Display profile at all.

    Any thoughts.
  2. JoeG4 macrumors 68030


    Jan 11, 2002
    Bay Area, Ca.
    That's just funny, but LED or CCFL backlit LCDs won't make a difference with text being 'fuzzy'.. That sounds like your anti aliasing settings changed (In appearance at the bottom - font smoothing).
  3. foodle macrumors 6502

    May 14, 2008
    Pennsylvania, USA
    The 24" iMac and 24" LED ACD use the same or very similar LCD panels (note this is just the panel, not the backlight). See:

    The 24" iMac does use a CCFL backlight, rather than LED however.

    Sharpness is a function of the panel, not the backlight, so that should not be evidence of the wrong backlight.

    A CCFL backlight can actually be brighter than a LED one, so brightness is also not a good way to tell what kind of backlight is there.

    However, you should look to see if the display needs to warm up or not. LED backlights reach a stable brightness in basically zero time. A CCFL backlight will require a number of seconds/minutes to reach a stable brightness.

    I think you need to clarify with Apple tech what they replaced and with what. The fact that the screen electronics is identifying itself as "iMac" is suspicious ...
  4. kretek thread starter macrumors member

    Oct 15, 2008
    Thanks for all the advise.

    I can only presume that the wrong panel was ordered.
  5. alphaod macrumors Core


    Feb 9, 2008
  6. late show macrumors member

    Nov 13, 2008
    I'm seeing this also after a repair.

    What happened in your case?
  7. Lennyvalentin macrumors 65816


    Apr 25, 2011
    It's not possible to mistakenly replace a LED-lit LCD panel with a CCFL-lit one. CCFLs need a totally different power supply than LEDs (high-voltage inverters, similar as used in overhead fluorescent tubes) while LEDs run on low-voltage DC.

    A Mac using a LED screen won't have the required power supply installed, so there'd be no way to power a CCFL screen... I would assume that either you're experiencing placebo effect (IE there's not actually any difference in the image, it's all just in your head :p), or the screen that was ordered and installed was bad, OR - probably most likely - some setting in your operating system has been changed and you just need to change it back to restore the appearance of your screen.

    Check that you have the correct color profile set, backlight brightness setting, screen resolution (wrong resolution can appear fuzzy) and so on.
  8. late show macrumors member

    Nov 13, 2008
    Good to know they not possible to mistakenly replace a LED-lit LCD panel with a CCFL-lit one.

    I took my 2009 24" LED Cinema Display in to apple this morning, they suggested that perhaps the display's logic board was damaged when they replaced the panel this week.

    iMac appears in both the system profiler and system prefs>displays with no brightness scroll/Imac profiles, this appears on different machines connected to the display.

    Before I took the display in I ran SwitchResX which showed the panel as: LM240WU6-SDA2 not coming up with much with that product # which is one number off the correct part #.

    I will post back once the repair is finished.

    Attached Files:

    • iMac.jpg
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  9. minifridge1138 macrumors 6502a

    Jun 26, 2010
    The Apple geniuses suggested that while replacing the display panel of a MONITOR, they damaged the logic board and now it shows up as an iMac?

    Ask them if they can damage a Toyota into a Ferrari.

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