Multi-information display (MID) pixel repair

    One of the returning issues with nineties BMW vehicles is fading or missing pixels, columns or lines in the liquid crystal displays (LCD) of instruments like radio and onboard computer. The multi-information display (MID) in the BMW 8 Series is no exception and many owners had to replace the unit at least once already. The issue is caused by deterioration of the flexible flat cable between LCD and printed circuit board (PCB). This flexible flat cable is a thin plastic film with conductive carbon traces printed onto that is glued to the LCD and PCB with thermal adhesive. With age, vibrations and temperature changes, the bond lets go and microscopic hairline cracks develop in the carbon traces. This leads to poor electrical contact. Sometimes the issue can be repaired by increasing the pressure on the flat cable where it attaches to board and display, but that often doesn't last or does not fix all pixel defects.



    The only proper and lasting fix is the replacement of the flexible flat cable with a new one. In the past this was the territory of professional repair shops, but nowadays the parts and tools can be obtained relatively cheap in online shops. All you need is a replacement flat cable and a soldering iron with specially designed T-tip to thermally glue the flat cable to LCD and PCB. It is not that difficult to replace the flat cable, but the glass substrate of the LCD is very thin and breaks easily. If you are not confident in attaching the new flat cable to the LCD yourself, some shops offer a complete kit of a brand new display with flat cable attached. The latter is also interesting to replace broken or scratched displays. I wrote an article that provides a step-by-step guide to replace the flat cable or display:

    Multi-information display pixel repair



    If interested, please read through the whole article before ordering parts online or trying to open the MID. If not fully confident you can perform the repair, it's best to leave it to professionals. It's very easy to break the MID and repair services may not accepts units that have been tampered with. Following people offer repair services (no affiliation and no personal experience - just listed because they are often recommended in the E31 community):

    If you want to give the DIY repair a try, you can get the parts from Tomas at German Auto Recycler (search the store for E31 ribbon and iron tool). Again no affiliation but the seller was correct and promptly answered questions. If you need additional instructions to open the MID, read MID OBC pixel repair attempt. That thread has good pictures of the disassembly.

    Hi Revtor,
    is Guido still doing them? I sent him mine in 2010 but he was having problems with the parts suppliers were sending him so he couldn't do mine, I got it back from him after about 10 months because there didn't seem to be and end to those issues on the horizon.

    93 850 CSI
    hung like Einstein, clever as a horse

    shiggsy: To be honest I don't know and I did not look into it, but after all this time you would expect the supplier issues to be resolved... You might want to drop him a mail.


    Anyone has good experiences with other repair services?

    Thanks very much for posting this Revtor, it will be very useful. A while back I managed to buy a replacement MID which worked perfectly. Now though the screen is suffering from the pixel failure problem and needs some work. I have an additional problem though, some of the buttons no longer work - do you happen to know if/how these can be repaired or replaced?
    Thanks
    Jason

    I feel I should point out that replacing the thin foam pressure strips that keep the ribbon cable pressed onto the contacts has resulted in 6 years of full pixel apparence on my MID. Definitely worth a go as a first shot as the foam in the form of double-sided tape is readily available and cheap.
    Of course, button issues are a different matter.


    MB

    Zitat von Argonaut;100034

    I have an additional problem though, some of the buttons no longer work - do you happen to know if/how these can be repaired or replaced?

    Anything can be replaced but finding the right spare parts is usually the biggest problem. Did you keep your old MID? If so, perhaps you could use it for spare parts?


    There is however one issue with exchanging button mechanism parts... I found there are two different (and incompatible) button mechanisms in use and I don't know for sure when the change occurred. It was probably with one of the part number changes, so make sure the MID for spare parts has the same part number.


    8Harry8: :mrgreen:


    MB: I know that several had success by increasing the pressure on the flat cable, but browsing through the archives of bimmerforums.com and roadfly.com just as many failed repair reports turned up. The MID in my article is one I use for testing purposes. It did have most of the clock area unreadable. I tried to repair it in the past by increasing the pressure on the flat cable as well, but it didn't work. Part of the flat cable had come apart from the PCB and irreversibly damaged the carbon traces on it. No amount of pressure could fix that. I guess it depends on where and how the damage to the flat cable occurred. The point is that increasing the pressure might work, but replacing the flat cable is guaranteed to fix the issue.

    Revtor,


    Point taken and I agree with you and your helpful guidance, I just think it is worth noting that the cheaper less involved action is a good first step, especially as in my case it worked very well.


    Cheers


    MB

    pixel repair


    I have had 1/2 a doz refurbished by Guido
    now and all working fine-- plus he is quick and not too expensive


    I recently asked if he could do The Bavaria Radio as well which he says he can
    so I recommend him


    jeff

    Radio ??


    Hey Harry


    what make of radio is that you have in your car
    All 3 of my Bavarias in the Csi's and 850's are gone
    and I cant find anything that fits
    your ideas ????

    Zitat von bm840ci;100544

    Hey Harry

    what make of radio is that you have in your car
    All 3 of my Bavarias in the Csi's and 850's are gone
    and I cant find anything that fits
    your ideas ????



    That's a Becker Indianapolis - fits in and matches the BMW set-up nicely, I have the same unit in my 8. One advantage is that it has built in satnav (albeit a bit clunky and old fashioned)
    Revtor produced a superb write-up on how to modify the screen so that the colour is a perfect match for the BMW, have a search and you will find it somewhere on the forum.

    Thanks a lot Revtor for this great how to! :top:
    I just replaced the flex cable and all pixels work now.


    A couple of comments for those who would also like to attempt this:

    • The ribbon cable to the keyboard is really stiff and it seems that the PCB and display unit is held by something else, but it's only the cable.
      It really needs to be bent (very carefully) above the white plastic (covering the end of the cable) or the length is not enough to remove the display unit.
    • for removing the residue of the old cable, Q-tips and wooden tooth pickers have proven to be the most effective (for me).
      (With these, the polarized film on top of the glass was not harmed by the solvent).
    • for gluing the cable to the display I used a large cardboard and sticked two layers of copy paper on top of it.
      That equals the thickness of the lower glass portion and gives perfect support for the iron tool. (Like in Revtor's drawing on the Wiki page).
      I taped the display to the cardboard so it couldn't move around.
    • aligning the cable to the barely visible traces takes time. Especially because on my replacement cable the traces were not a perfect fit.
      They were a bit short so on both ends they had to be closer to the center.


    It's a bit fiddly job but with a calm hand it can be done.


    Cheers,
    Steve

    Radio ??


    Zitat von revtor;100033

    shiggsy: To be honest I don't know and I did not look into it, but after all this time you would expect the supplier issues to be resolved... You might want to drop him a mail.


    Anyone has good experiences with other repair services?



    Hi Revtor
    in the add above there was a picture of a strange radio in someones car
    which * Harry tells me is yours
    could you please share with me what make and model it is because
    I have a Csi and 2 85o's that need new radios and im battling to find on ethat fits
    ths a lot


    Jeff

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