Inverter broken? (2008 Core2Duo 2.4 GHz)

Discussion in 'MacBook' started by Beliblis, May 14, 2012.

  1. Beliblis macrumors regular

    Dec 31, 2011

    I've got a very weird screen behaviour going on. Not sure if it is the inverter. In a nutshell: the backlight goes off. Then sometimes it comes on again.
    I don't think it's a graphics card problem - with an external screen, things are fine.
    Also: If I look very closely, I can see the screen content without the backlight. (Same as when you dim down the display the whole way).

    I might be wrong, but it seems like on the bottom left of the screen (when it's working), just next to the hinge, the display brightness isn't the same as in the rest of the screen.... though that may be subjective, me "seeing things".

    As I said - my guess would be: inverter, or inverter cable.

    What's weird though:
    1) The problem started 3-4 months ago, but only happened at a certain screen angle (when it was 2 inches/10 degrees opened).

    2) Then the problem started happening at other screen angles. I took the laptop apart, keyboard unit off, everything back together: works fine.
    A day or two later: buggered again.

    3) For some time, I noticed that when the screen goes dark, I could press the keyboard unit down near the FireWire port. That fixed the problem. So I thought: maybe a loose connection somewhere?
    Sometimes, "pulling up" on the top right screen edge and slightly(!) pressing down the laptop near the magsafe connector, helped solve the problem.
    (Once the screen was working, I just kept it in that position & didn't touch it.

    But now all this doesn't help anymore either. Screen's working, I walk away make coffee, come back: backlight is off. A few minutes later it sometimes comes on again by itself...

    Long story cut short: It's just plain weird.... as if my little Macbook had a life of its own.

    Any ideas anyone?
  2. logana macrumors 65816


    Feb 4, 2006
    sounds like the inverter to logic board cable is faulty - cheap fix if you can DIY
  3. Beliblis thread starter macrumors regular

    Dec 31, 2011
    DIY is no problem. Are you sure it's the inverter cable, and not the inverter?
    (I guess a faulty inverter would not be intermittent, or dependent on screen angle right?)

    The 2.4 GHz MacBook Core2Duo is a "Penryn" model, right?
    I know there's two different inverter cables for the MacBooks. If I go through eBay, sellers might not be clued up.
    Is it possible to visually distinguish the 2 different inverter cable models? I mean - do they have different number of connections or pins?
    I'v currently pulled mine out from the logic board (writing this post on a friend's laptop). It's a 4-pin connector.
  4. davidg4781 macrumors 68020

    Oct 28, 2006
    Alice, TX
    I was having almost the exact same issues as you with my 2006 CD MacBook. I was all set to try replacing either the inverter cable or board myself. I then phoned an Apple Store to ask how much they would charge. I think they said $50 for parts and labor, but I remember it was a lot less than what the parts plus shipping would have cost me.

    Also they know what they're doing and if they good it up it's covered. I took it to them and they charged me $5 for the cable and $0 for labor since they replaced a cracked top case.
  5. gumblecosby, May 14, 2012
    Last edited: May 14, 2012

    gumblecosby macrumors 6502

    Jun 22, 2010
    Im going to be doing this shortly myself. I have ifixit's guide ready:

    My problem is the same as your but at a more advanced stage. It takes a lot of back and forth movement to get the backlight on now. I came to the same conclusion as you in that it must be the cable not the board.

    I was looking on ebay a while back for parts. Most sellers mentioned which kind of cable or inverter they had as well as a picture of it to help differentiate the various kinds of parts.
  6. Beliblis thread starter macrumors regular

    Dec 31, 2011
    I'm not sure if it is actually the cable:

    Last time the screen went black, I connected my external screen, then selected "detect displays" in my finder menu. Then the internal screen came back on again – the VERY same second the system did a ping for the screens...

    Maybe BOTH the inverter & the cable are broken.

    Could it be possible that my initial problem was the cable, and through intermittent connections, the inverter now got damaged as well?
  7. Beliblis thread starter macrumors regular

    Dec 31, 2011
    OK. Here's the problem with spare parts on eBay (from what I understand):

    Most cables I find on eBay are for the "A1181" Macbook model. But that could be anything from a 1.83 GHz Core Duo to a 2.4 GHz Core 2 Duo.

    But: according to iFixit, there is a difference between the 1.83 Core Duo and the later (Penrun/Santa Rosa) models. See Step 33 on this guide:

    Also, see this thread:
  8. davidg4781 macrumors 68020

    Oct 28, 2006
    Alice, TX
    Any reason why you don't want to go through Apple? Maybe you can buy the part from them? My brand new genuine Apple inverter cable was only $5 compared to I think $20 online.
  9. InuNacho macrumors 65816


    Apr 24, 2008
    In that one place
    How long ago did you have the inverter cable replaced?
  10. davidg4781 macrumors 68020

    Oct 28, 2006
    Alice, TX
    Last April. I remember it was around my birthday.
  11. Beliblis thread starter macrumors regular

    Dec 31, 2011
    Buying direct (and repairing myself): not possible to buy spare parts. I've just contacted Apple UK (Regent Street Flagship Store) – "the only spare part we sell for this model is the battery". They referred me to – which is useless, as I want to do the repair myself.

    "Apple Authorized Service Center" – same here. No spare parts, only overpriced repairs which take too much time as well. (I've got an external screen, so can use my laptop at home & can't live without it for a whole week).

    "Genius Bar" - yeah right, try and get a slot in the genius bar here in London. (Apart from the time & effort involved of getting there, just to be told "you got to leave your laptop, we'll be in touch when it's repaired).
  12. davidg4781 macrumors 68020

    Oct 28, 2006
    Alice, TX
    Ahh. For me I got a slot right away at a Genius Bar. Was told it would be $50 total over the phone. Got there and they said $5 or $20, depending if it's the board or the cable. I did have to pick it up a few days later but I saved money (probably not much because of the drive) and I know I didn't goof anything up.

    I've never opened a laptop and I was reading about how tight the spaces are. Not that I was worried about it, but if I was going to save money to have someone else do it I chose that.
  13. mykweb macrumors member

    Feb 4, 2011
    If you are in the uk try this place

    I bought a few parts from them for my late 07 macbook. I requied the keyboard ribbon, the invertor and the screen cable. Total cost was around £30 and it sorted out all my issues. Used ifixit to follow the guides :)

  14. Beliblis thread starter macrumors regular

    Dec 31, 2011
    SO, I've just replaced the inverter cable. And the screen is STILL intermittent.
    Could it be that an inverter is intermittent?

    I've been using the laptop back home without moving it for quite a few days. (External monitor attached, so I can work).
    Sometimes the screen comes on for hours no problem, then off for a day, then on for a minute,.... very irregular behavior.

    Not sure if I should buy an inverter off ebay now.
    I would have thought an inverter is either working, or not working. No?

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