Mercedes-Benz Forum banner

Instrument Cluster Pixel Fix

166K views 133 replies 71 participants last post by  jim9  
#1 ·
Hello, I'm kind-of new here; been lurking a lot. After looking everywhere for a good way to fix the missing pixel problem in my C208 and not finding an convincing enough method (except a new replacement unit, which would be rather silly), I decided to take mine apart and brain-storm. This is what I found and how I decided to go about fixing it.

The problem with the ribbon connection points in these VDO units, it's in the lousy way they are held together, there is not a single screw holding these things together, it's all tabs. An example of how it should have been done is the center (main) display ribbon connection; it's held down firmly at the circuit board end by a proper connector latch. The ribbons of the smaller screens are glued-on and held-down by small silicone strips, the glue itself is part of the problem as it softens with heat and some residue gets in between the contact points. The pressure exerted by the silicone strips is dependent on the assembly being held together by all the tabs, and it's obviously not enough after a while, so I decided to use screws to provide the clamping force.

This was my first attempt to repair this and I did it rather hastily, nevertheless I am very pleased with the results. I now have a better idea of what to do to ensure a perfect, more permanent fix; for example this is what I didn't do but would if I did this again:

Apply radiant heat to ribbon connection at circuit board to separate it completely, clean it, and reattach it (no glue this time), then spraying some silicone lubricant to keep moisture out.
If you don't want to do this, I recommend spraying the connection with circuit board cleaner prior to going over the ribbon with the soldering pencil.

But, as you will see, the result is rather good as it is. Anyone can do this, it just requires a lot of patience, por example, most people are scared of damaging something when removing the gauge needles, (but damage is more likely if you attempt to pry them straight out), I found that keeping the dust out of the screens and inside of front lens was far more challenging.

Parts used:

(4) Phillips screws (4/32" X 3/8").
(4) Washers (5/16" total diameter). Plastic is preferable but metal ones insulated with tape will work.
Soldering iron (pencil type, do not use pistol type as these heat-up too quickly).
Drill bit (5/64").
Two strips of high density foam (a mouse pad will work) about 1.5" X 5/16"
Mini-screwdriver set.
 
#2 ·
When working on electronic circuits such as this, take precautions to prevent static electricity arcing by grounding yourself with a specialised bracelet, Radio Shack sells them cheap. Alternatively, "discharge" yourself by periodically touching the ground as you work along. This is very important, as one single spark can potentially ruin your cluster.



Image


Image


Image


Image


Image
 
#3 ·
When re-installing the needles, do not push them straight down. Do this instead:

Position needle at 12:00 o'clock on shaft and gently push down just a bit, just enough so the needle and shaft will spin as one. Spin the needle down to zero and press down simultaneously, tap it down the rest of the way with a rubber-handled screwdriver or other soft object, BE CAREFUL as it is possible to tap it too far and the needle base will contact the dial face. It is a good idea to measure how high the needle sits before removing it (I forgot to add this caption to one of the photos).
From there, you can zero the needle by pushing it towards the zero mark if it sits too high, or spinning it around clockwise and pushing it past the stop if it sits too low. This requires many attempts to achieve, don't worry, those little motors seem to be very sturdy.

Image



Image


Image


Image


Image
 
#11 ·
See pictures 6 and 7 of post #5

Those tabs are the only thing holding the white assembly and
pressing the ribbons against the circuit board. If you add pieces of
high density foam to increase pressure on the ribbons, these tabs
don't hold, and keep popping out.

The screws take the load off the tabs and exert constant clamping force
on the ribbon connection.

It'll all make sense when (or if) you take the thing apart,
you'll see what I'm referring to.
 
#13 ·
I am unaware if someone else has tried it. Some people are intimidated
because these are delicate, precision instruments.

I decided to do it because I got tired of not finding a definitive solution,
it was a gamble, but I'm glad I did.

The important part is to apply heat to the connections as described,
it will also help if you spray some contact cleaner before applying heat.

So far, mine is still working perfectly.
 
#15 · (Edited)
The needles go in about the same way you pull them out, but, as I described it;
tap them the rest of the way down to the correct height, once they're in place
you can start playing with the adjustment, winding them back and forward
until they sit where you want them.

Play with them a little before you remove them so you can feel the "stops"
at zero and all the way around past the 160 mph mark, you push past these stops to adjust them, meaning that you're basically forcing the
needle to slip over the shaft.

I will try to take pictures of the procedure if this is still not clear enough,
I need to replace some bulbs, so I'll be taking my cluster out again.
 
#42 ·
Great Job



Really a great job Dantus, I once had mine with the foam, but I still have some missing pixels, so I'm going to have it another try using your way to fix it, but I'm still afraid removing the needles the time the discribtion in that picture was not clear for it was typed in red... co could you please describe that part again, and if you can support that with pictures it would be more helpful, for I still don't have the courage to pull the needles I'm afraid to break them, and to break them it means 1000$ to have a new instrument, ha ha .... please advice....
Thank you again,
 
#23 ·
YES it is very easy to do...



it slips right out. you can use a suction cup to remove it, or you can slip a clothing hanger in the sides over a credit card (so you dont damage the leather) and hook it out...

make sure your steering wheel is pulled all the way out****
 
#25 ·
Be careful..

I've removed the cluster in my W208 several times to fix the clock and tempearature displays. I wasn't careful the last time and the ribbons came off the circuit board. I just put them back without soldering them and only using the pressure from the pads that were already there. Needless to say, both LCDs are not working.:( I wonder if I can re-solder the ribbons back. If someone has already done this, I could use some help...
 
#26 ·
Yes it happened to me. My problem was only on the clock. You may have an error now saying cluster malfunction if the ribbon isn't touching the proper leads. What you can do is place the ribbon back exactly where they came off. Heat up the ribbon just enough to get the green glue under it hot enough for it stick. Not to much or you will burn the ribbon. Your main goal now is forget about getting the lcd to work and protect your cluster from saying instrument malfunction.
 
#28 ·
Thanks for the great write-up. Looks like a good bit of work but I'll probably tackle this soon. The one part that seems scary is the needles.

If things don't go perfectly I had been planning to just disconnect the left hand side (temp) readings.. sounds like that would throw an error - perhaps I'll just cover it up with some thin black plastic. Might just do that on both sides since the data is pretty worthless (except for the gear info, unfortunately)