Here's the step by step process..
1. Remove the MID unit from the center console, some people mentioned that you need to remove a nut under the volume knob, I realized that I just had to slowly with a flat head screw driver pry at the sides of the MID unit and it slowly popped out. Suggest that you wrap the head of the screw driver with a cloth to prevent scratches
2. With the MID Unit removed, remove the 8-9 torox screws and the front display should separate itself from the metal casing, dont yank it apart just yet coz the display is connected via the ribbon cable and also 3 connectors.
3. The metal casing can actually be dismantled and it needs to be to get at the insides, to remove the 3 connectors. Refer to the picture below; the red arrows indicate the piece that can be slowly taken off, its not being held in place by any screws. Again with a flat head in the slots, slowly pry it open.
4. Now with the top metal cover off, disconnect the 3 connecters (red arrows)
5. There is also 3 torox screws holding the actual display board to the front black panel, remove those. So what your left with should look like the picture below;
6. The good stuff is actually the ribbon connecting the display to the main circuit board, it seems that the connection between the ribbon cable and the mail circuit board degrades overtime, so the objective here is to cleanup and reattached the ribbon cable to the main circuit board.
7. There is a metal strip that applies pressure to the ribbon cable to circuit board connection, remove that and also the pink rubbery stuff also. I didnt manage to take any of my own pictures so I borrowed the ones from bimmerboard (thank you visionbmw7)
Remove the metal strip
Carefully separate the ribbon cable and pink strip from the circuit board, be very careful here and you need to apply even pressure to avoid deforming the ribbon cable.
8. Next step, is to clean up the glue and residue on both the circuit board connector and also the ribbon cable, acetone was recommended but I have no idea where to get acetone, also didnt know the chinese translation so malas to ask hardware shop. Instead I use nail polish remover and Qtips. You will need to apply some pressure and I used quite alot of nail polish remover. Below is the before cleaning and after cleaning pictures.
Before - notice the discoloration
After - all nice and clean
9. So thats the circuit board side done, next part is the ribbon cable, you will probably notice that there is no longer any circuit tracks at the ends of the ribbon, I supposed they just degraded with time, the trick here is to salvage the unexposed tracks. Again using Qtips and nail polish remover, just desolve and clean up the glue.
Here's a picture of the ribbon cable before cleaning, notice there isnt any tracks at the ends of the cable.
Here's the picture of the ribbon cable after cleaning, the salvaged tracks are circled in red. We'll be connecting the salvaged tracks to the connectors on the circuit board.
10. Next, line up the ribbon cable to the circuit board, make sure all the connectors line up and I used tape to stick'em together. So you need to tape both sides, front and back. I used a camera with macro to take pictures of the alignment as I didnt have a magnifying glass on hand.
11. Put the pink strip back in place but using the side without the indents facing towards the circuit board and slip on the metal strip. Its pretty important to make sure you stuff the pink strip nicely into the metal strip grove to ensure the contact between the circuit board and ribbon cable is good. Should look like this...almost done now.
12. So before putting everything back together, test out the repair in the car and depending on how good the ribbon to circuit board alignment it, you may need to give it a couple of tries. I personally had it do it 4 times to get it right.
13. Once your happy, just put everything back together, remember to reattached the 3 connectors to the display before closing up the unit. Reattach the MID to the car and PRESTO...
AFTER
The entire DIY took 3-4 hours out of my saturday afternoon, i will post up some more pictures and some steps which wasnt covered in the bimmerboard DIY guide.
